There are 5,040 different ways in which she can order the books.
In how many ways can she put the books on the shelf?We know that Donna has 9 books, but 2 of these books already have fixed positions (the first one and the last one).
So we only need to order the remaining 7 books in 7 positions.
On the first position, we have 7 options (7 books to put there).On the second position, we have 6 options (because one book is already in the first position).On the third position, we have 5 options.And so on for the remaining positions.
The total number of different combinations in which she can order the books is given by the product between the numbers of options above, so we will get:
C = 7*6*5*4*3*2*1 = 5,040
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Let Xi = (i =1,2,3) be independently and normally distributed random variable with mean of 4 as variance i. state the distribution of the following random variable
i) V = X1+X2+X3
The sum of normally distributed random variables is also a normally distributed random variable.
Given [tex]n[/tex] random variables with [tex]X_i\sim\mathrm{Normal}(\mu_i,\sigma_i^2)[/tex], their sum is
[tex]\displaystyle\sum_{i=1}^n X_i \sim \mathrm{Normal}\left(\sum_{i=1}^n \mu_i, \sum_{i=1}^n \sigma_i^2\right)[/tex]
i.e. normally distributed with mean and variance equal to the sums of the means and variances of the [tex]X_i[/tex].
In this case, each of [tex]X_1,X_2,X_3[/tex] are normally distributed with [tex]\mu=4[/tex] and [tex]\sigma^2[/tex] = ... I'm not sure what you meant for the variance, so I'll keep it symbolic. Then
[tex]V = X_1+X_2+X_3 \sim \mathrm{Normal}(12, 3\sigma^2)[/tex]
Mike drove 40 miles from his home to his office, and he then drove back home using the same route. The average speed on his return trip was 10 miles/hour more than the average speed on his trip to the office. The total time for the trip is represented by this expression, where x is the average speed on the trip from his home to his office.
The average speed on Mike’s drive home is represented by
x + 10
.
When Mike drives at an average speed of 55 mile/hour on his way home, it takes him approximately
1.6 hours
to drive to work and back.
Mike's speed driving to his office is 45 miles/hour, which is 10 miles less than his average speed driving back.
How is speed calculated?Speed is an average value of a scalar measurement of the distance covered over the time taken.
Speed is the equation, r = d/Δt, where r = speed or rate, d = distance, and Δt is the change in time.
Thus, when the distance covered by a traveler is divided by the time consumed, one can determine the average speed for the travel.
Data and Calculations:Distance from Mike's home to his office = 40 miles
Distance to and from = 80 miles (40 miles x 2)
Hours covered from office = 1.6 hours
Average speed for the trip = 50 miles/hour (80/1.6)
Average speed to return home = 55 miles/hour
Average speed to office = 45 miles/hour (55 - 10)
Thus, Mike's speed of driving to his office is 45 miles/hour.
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Question Completion:What is Mike's speed driving to his office?
Which rule describes the relationship between the x- and y- coordinates on the following graph? Choose 1 answer:
(Choice A)
A
y
=
2
x
y=2xy, equals, 2, x
(Choice B)
B
y
=
x
+
2
y=x+2
Answer:
A
Step-by-step explanation:
given the points
(0, 0 ) , (2, 4 ) , (4, 8 )
note that the y- coordinate is twice the value of the x- coordinate , so
y = 2x
AN aquariums dimension are 3 1/4 x 2ft x 1 3/4. what is the volume of the aquarium
The volume of the rectangular prism aquarium = 17 1/16 ft.
What is the Volume of a Rectangular Prism?Volume of a rectangular prism = (l)(w)(h), where:
Length of the prism = lWidth of the prism = wHeight of the prism = hThe aquarium is a rectangular prism. Its dimensions are given as:
Length (l) = 3 1/4 ft
Width (w) = 3 ft
Height (h) = 1 3/4 ft
Substitute
Volume of the rectangular prism aquarium = (3 1/4)(3)(1 3/4)
Volume of the rectangular prism aquarium = (13/4)(3)(7/4)
Volume of the rectangular prism aquarium = (13 × 3 × 7)/(4 × 4)
Volume of the rectangular prism aquarium = (273)/(16)
Volume of the rectangular prism aquarium = 17 1/16 ft.
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How does the area below the mean compare to the area above the mean in a normal distribution?
The area below the mean compares to the area above the mean in a normal distribution as the areas are always equal regardless of the mean. Option A This is further explained below.
What is a normal distribution?Generally, The normal distribution, also known as the Gaussian distribution, is a kind of probability distribution that is symmetric around the mean. This means that it demonstrates that data that are closer to the mean are more likely to occur than data that are farther away from the mean. When represented graphically, the normal distribution takes the shape of a "bell curve."
In conclusion, In a normal distribution, the area below the mean is compared to the area above the mean since the areas are always equal regardless of the mean. This is true even if the mean is different.
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Complete Question
How does the area below the mean compare to the area above the mean in a normal distribution?
A. the areas are always equal regardless of the mean
B. the areas are sometimes equal depending upon the standard deviation of the distribution
C. the area above the mean is larger since the values are larger as you move above the mean
D. the areas are sometimes equal depending upon the value of the mean
1. What is the measure of angle x?
Answer: 60
Step-by-step explanation:
Almost everything in this picture is irrelevant to finding the measure of x.
x = 180 - 90 - 30 = 60
7. Find (f•g)(x) for the pair of functions.
f(x)=x+1
g(x) = 4x - 11
(f•g)(x) =
Answer:
(f•g)(x) = 4x² -7x -11
Step-by-step explanation:
The product of the two functions is the product of their respective definitions.
(f•g)(x)(f•g)(x) = f(x)•g(x) = (x+1)•(4x -11)
= x(4x -11) +1(4x -11) . . . . . use the distributive property
= 4x² -11x +4x -11 . . . . . . . and again
(f•g)(x) = 4x² -7x -11 . . . . . collect terms
Let f(x) = cxe−x2 if x ≥ 0 and f(x) = 0 if x < 0. For what value of c is f a probability density function? for that value of c find P(1
The value of c such that the function f is a probability density function is 2
How to determine the value of c?The density function is given as:
f(x) = cxe^(−x^2) if x ≥ 0
f(x) = 0 if x < 0.
We start by integrating the function f(x)
∫f(x) = 1
This gives
∫ cxe^(−x^2) = 1
Next, we integrate the function using a graphing calculator.
From the graphing calculator, we have:
c/2 * (0 + 1) = 1
Evaluate the sum
c/2 * 1 = 1
Evaluate the product
c/2 = 1
Multiply both sides of the equation by 2
c = 2
Hence, the value of c such that the function f is a probability density function is 2
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Any help with this greatly appreciated.
Put the equation in standard linear form.
[tex]x'(t) + \dfrac{x(t)}{t + 5} = 5e^{5t}[/tex]
Find the integrating factor.
[tex]\mu = \exp\left(\displaystyle \int \frac{dt}{t+5}\right) = e^{\ln|t+5|} = t+5[/tex]
Multiply both sides by [tex]\mu[/tex].
[tex](t+5) x'(t) + x(t) = 5(t+5)e^{5t}[/tex]
Now the left side the derivative of a product,
[tex]\bigg((t+5) x(t)\bigg)' = 5(t+5)e^{5t}[/tex]
Integrate both sides.
[tex](t+5) x(t) = \displaystyle 5 \int (t+5) e^{5t} \, dt[/tex]
On the right side, integrate by parts.
[tex](t+5) x(t) = \dfrac15 (5t+24) e^{5t} + C[/tex]
Solve for [tex]x(t)[/tex].
[tex]\boxed{x(t) = \dfrac{5t+24}{5t+25} e^{5t} + \dfrac C{t+5}}[/tex]
Take 4x + 2 from 8x + 5.
4x + 3
4x - 3
-4x - 3
Answer:
4x + 3 just take away rhe values
Proofs and congruent triangles ( serious full answers only or 1 star and report )
Answer:
There are 5 ways to find if two triangles are congruent.
SSS- {Side Side Side Congruence.}
This law of congruence states that if we have two triangles, each with the same measures on each 3 sides it deems the triangles congruent.
SAS- {Side Angle Side Congruence.}
This law of congruence states that if we have two triangles, with 2 equal sides and one angle which is common among them; the triangles are congruent.
ASA- {Angle Side Angle Congruence.}
This law of congruence states that if we have two triangles, with 2 congruent angle measures and 1 congruent side; the triangles are indeed congruent.
AAS- {Angle Angle Side Congruence.}
You may be wondering how this law of congruence differs from the previous one. ASA refers to any two angles and the included side, whereas AAS refers to the two corresponding angles and the non-included side.
HL- {Hypotenuse Leg Congruence.}
This law of congruence states that if we have two triangles, with a common (congruent) leg and hypotenuse; the triangles are congruent.
I really hoped this helped, if it didn't leave a comment I am always open to feedback. If it did let me know, brainiest is always appreciated!
Hope you have a great rest of your day.
Answer:
Step-by-step explanation:
for completeness, here is the answer again:
1 Given is correct
2 Definition of right angle is correct
3 should be sum of interior angles in a triangle
4 is substitution
5 subtracting 90degree from left and right hand side
6 is definition of complementary angles
Part of the arena is being turned into a public darkroom. The floor needs covering in rubber tiles before work can begin on the dark room. The tiles are 20 cm by 30 cm. The dark room floor is 6 metres by 3 metres. Are 280 tiles enough? How many more/less tiles are needed?
The number of tiles used is 300 tiles.
According to the statement
We have given that:
The tiles are 20 cm by 30 cm. And the dark room floor is 6 meters by 3 meters.
And we have to find that the number of tiles used to prepare the dark room.
So, For this purpose we have to find the area of the room floor.
The area of the floor is 6 *3.
The area of the floor is 18 meter per square.
The area of the tile is 0.2*0.3
The area of the tile is 0.06 meter per square.
Now,
The number of tiles used is 18/0.06
The number of tiles used is 300.
So, The number of tiles used is 300 tiles.
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In a mathematics class, 24 students received an A on the third test, which is 150% of the students who received an A on the second test. How many students received an A on the second test
Answer: 16
Step-by-step explanation:
1.5x = 24
24/1.5 = 16 students.
domain of f(x)=(1/4)^x
What is the domain of f(x)
O A. x>0
OB. All real numbers
O C. y>0
O D. x<0
? Need help asap
Answer: B
Step-by-step explanation:
The domain of a function is the set of x-values.
B) Using the two point above find the slope using the formula m =
y/₁y₁
x₂-1
C) Plug in your slope and one of the two points above into point-slope formy - y₁ = m(x-x₁)
D) Change above equation into slope-intercept form y = mx + b. (See page 5 in lesson 5.06).
16+20
The linear equations are y - 25 = 0.89(x - 20) and y = 0.89x + 7.2
The slope of the lineThe complete question is added as an attachment
The two points from the graph are (20, 25) and (38, 41)
The slope of the line is calculated using
m = (y2 - y1)/(x2 - x1)
Substitute the known values in the above equation
m = (41 - 25)/(38 - 20)
Evaluate
m =0.89
The linear equation in point slope formThis is calculated as:
y - y1 = m(x - x1)
Substitute the known values in the above equation
y - 25 = 0.89 * (x - 20)
Evaluate
y - 25 = 0.89(x - 20)
The linear equation in slope-intercept formWe have:
y - 25 = 0.89(x - 20)
Expand
y - 25 = 0.89x - 17.8
Add 25 to both sides
y = 0.89x + 7.2
Hence, the linear equations are y - 25 = 0.89(x - 20) and y = 0.89x + 7.2
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Is the following relation a function?
Evaluate each expression if A=2
B=-3. C=-1. D=4
2d-a/b
Answer:
2 × 4 - 2 / -3
8-2/-3
6/-3
-2
Joseph is planning dinners for the next 4 nights. There are 10 meals to choose from. If no meal is repeated, how many different meal arrangements are possible?
Considering the definition of combination, if no meal is repeated, 210 different meal arrangements are possible.
What is combinationCombinations of m elements taken from n to n (m≥n) are called all the possible groupings that can be made with the m elements in such a way that not all the elements enter; the order does not matter and the elements are not repeated.
To calculate the number of combinations, the following formula is applied:
[tex]C=\frac{m!}{n!(m-n)!}[/tex]
The term "n!" is called the "factorial of n" and is the multiplication of all numbers from "n" to 1.
Different meal arrangementsJoseph is planning dinners for the next 4 nights. There are 10 meals to choose from and no meal is repeated.
So, you know that:
m= 10n= 4Replacing in the definition of combination:
[tex]C=\frac{10!}{4!(10-4)!}[/tex]
Solving:
[tex]C=\frac{10!}{4!6!}[/tex]
[tex]C=\frac{3,628,800}{24x720}[/tex]
[tex]C=\frac{3,628,800}{17,280}[/tex]
C= 210
Finally, if no meal is repeated, 210 different meal arrangements are possible.
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What else would need to be congruent to show that ABC DEF by SAS? E AA. А B OA. BC = EF B. CF OC. ZA ZD D. AC = OF F Given: AC = DF CE F
The two triangles exist congruent if they contain two congruent corresponding sides and their contained angles exist congruent.
Let [tex]$&\overline{A B} \cong \overline{D E} \\[/tex] and [tex]$&\overline{A C} \cong \overline{D F}[/tex]
Angle between [tex]$\overline{A B}$[/tex] and [tex]$\overline{A C}$[/tex] exists [tex]$\angle A$[/tex].
Angle between [tex]$\overline{D E}$[/tex] and [tex]$\overline{D F}$[/tex] exists [tex]$\angle D$[/tex].
Therefore, [tex]$\triangle A B C \cong \triangle D E F$[/tex] by SAS, if [tex]$\angle A \cong \angle D$$[/tex].
What is SAS congruence property?Given:
[tex]$&\overline{A B} \cong \overline{D E} \\[/tex] and
[tex]$&\overline{A C} \cong \overline{D F}[/tex]
According to the SAS congruence property, two triangles exist congruent if they contain two congruent corresponding sides and their contained angles exist congruent.
Let [tex]$&\overline{A B} \cong \overline{D E} \\[/tex] and [tex]$&\overline{A C} \cong \overline{D F}[/tex]
Angle between [tex]$\overline{A B}$[/tex] and [tex]$\overline{A C}$[/tex] exists [tex]$\angle A$[/tex].
Angle between [tex]$\overline{D E}$[/tex] and [tex]$\overline{D F}$[/tex] exists [tex]$\angle D$[/tex].
Therefore, [tex]$\triangle A B C \cong \triangle D E F$[/tex] by SAS, if [tex]$\angle A \cong \angle D$$[/tex].
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Numbers from 1 to 50.
Find the probability of choosing
numbers with last digit 6.
0.1 or 10%
Step-by-step explanation:The numbers between 1 and 50 that end in 6 are as follows:
6, 16, 26, 36, 46
There are therefore 5 numbers between 1 and 50 that end in 6.
This means there are 5 out of 50, or 5/50.
5/50 is 0.1 as a decimal, or 10% in percentage form.
Urgent help needed will give brainiest
We can write the integration domain as
[tex]D = \left\{(x,y) \mid -1 \le y \le 1 \text{ and } 2y-2 \le x \le -y+1\right\}[/tex]
so that the integral is
[tex]\displaystyle \iint_D -\sin(y+x) \, dA = \int_{-1}^1 \int_{2y-2}^{-y+1} -\sin(y+x) \, dx \, dy[/tex]
Compute the integral with respect to [tex]x[/tex].
[tex]\displaystyle \int_{2y-2}^{-y+1} -\sin(y+x) \, dx = \cos(y+x)\bigg|_{x=2y-2}^{x=-y+1} \\\\ ~~~~~~~~ = \cos(y+(2y-2)) - \cos(y+(-y+1)) \\\\ ~~~~~~~~ = \cos(3y-2) - \cos(1)[/tex]
Compute the remaining integral.
[tex]\displaystyle \int_{-1}^1 (\cos(3y-2) - \cos(1)) \, dy = \left(\frac13 \sin(3y-2) - \cos(1) y\right) \bigg|_{y=-1}^{y=1} \\\\ ~~~~~~~~ = \left(\frac13 \sin(3-2) - \cos(1)\right) - \left(\frac13 \sin(-3-2) + \cos(1)\right) \\\\ ~~~~~~~~ = \boxed{\frac13 \sin(1) - 2 \cos(1) + \frac13 \sin(5)}[/tex]
Please put answer as a mixed number! :)
1 and 3/8* 1.5 + 5 and 5/8 ÷ 0.4 =
Answer: 7 1/16 and 1 9/16
Step-by-step explanation: 1 3/8 x 1.5 is 1 3/8 x 1 5/10 11/8 x 15/10 which is 165/80. We divide it by 5/5 to get 33/16. This as a mixed number is 2 1/16. We add 5 to get 7 1/16.
5/8 divided by 0.4 is 5/8 divided by 2/5. We divide this by first finding the reciprocal of 2/5 which is 5/2. 5/8 x 5/2 = 25/16. This as a mixed number is 1 9/16.
What is the domain of f(x)=(1/3)^x
Answer:
All Real Numbers
Step-by-step explanation:
The domain is all the x values for a function. As this function is not restricted in any way, the domain is all real numbers. You can put any number in for x and plot it on the graph.
A book sold 42,600 copies in its first month of release. Suppose this represents 9.2% of the number of copies sold to date. How many copies have been sold to date?
Answer:
We lend 100% - 9.2% and this will equal 90.8%, then we will make this percentage of 42,600 which will give us 38,680 and we will add the 42,600 and this will give us a total of 81,460 copies.
An administrator surveys a random sample of 48 out of 900 middle school
students. Using the survey results, the administrator estimates that 225 students
are in favor of the new dress code. How many of the 48 students surveyed were
in favor of the new dress code?
Considering the definition of probability, 12 of the 48 students surveyed were in favor of the new dress code.
Definition of probabilityProbability is the greater or lesser chance that a given event will occur.
In other words, the probability establishes a relationship between the number of favorable events and the total number of possible events.
Then, the probability of any event A is defined as the ratio between the number of favorable cases (number of cases in which event A may or may not occur) and the total number of possible cases. This is called Laplace's Law.
P(A)=number of favorable events÷ number of total events
Probability that students are in favor of the new dress codeIn this case, you know:
Total number of middle school students = 900 (number of possible cases)The number of students are in favor of the new dress code = 225 (number of favorable cases)Replacing in the definition of probability:
P(A)=225 students÷ 900 students
Solving:
P(A)= 0.25
Expressed as a percentage:
P(A)= 25%
Number of the 48 students surveyed were that in favor of the new dress codeIn this case, you know:
Total number of middle school students = 48 (number of possible cases)25% students are in favor of the new dress code (P(A)= 25%= 0.25)Replacing in the definition of probability:
0.25=students in favor of the new dress code÷ 48 students
Solving:
students in favor of the new dress code= 0.25×48 students
students in favor of the new dress code= 12 students
Finally, 12 of the 48 students surveyed were in favor of the new dress code.
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how do you compare and contrast the steps of two different constructions using a compass?
In order to compare and contrast the steps of two different constructions using a compass, we simply take a note of the different steps followed in both the constructions.
How to compare and contrast the steps?
For both the constructions, observe the corresponding steps steps that have been performed in order.
Then, note down what similarity you find while constructing the two different constructions in the first step.
Once you know the the similarities, you can further trace down the differences in the procedure of the two constructions by observing the first step. This is how you can compare and contrast the first step of two different constructions using a compass.
This process can be followed for all the steps for comparing and contrasting two different constructions.
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A container manufacturer plans to make rectangular boxes whose bottom and top measure 2x by 3x. The container must contain 12in.3 The top and the bottom will cost $2.60 per square inch, while the four sides will cost $4.30 per square inch. What should the height of the container be so as to minimize cost? Round your answer to the nearest hundredth.
The height of the container be so as to minimize cost will be 1.20. inches.
How to calculate the height?The volume of the box will be:
= 2x × 3x × h
= 6x²h
Volume = 6x²h
12 = 6x²h
h = 2x²
The cost function will be:
C = 2.60(2)(6x²) + 4.30(12x)h
C = 31.2x² + 51.6xh
Taking the derivative
62.4x + 51.6h
h = 1.20
Therefore, the height of the container be so as to minimize cost will be 1.20 inches.
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Difference of Squares gives which complex factors for the expression +3?
A. (x+3i)(x-3i)
B. (x-i-√3)(x-i√3)
C. (x+3i)^2(x-3i)²
D. (x+i√3)(x-i√3)
The difference of squares is:
(x+i√3)(x-i√3)
So the correct option is the last one, D.
Which expression gives x^2 + 3?For a complex number:
[tex]Z = a + b*i[/tex]
We define the complex conjugate of Z as:
[tex]Z' = a - b*i[/tex]
Such that the product between the complex number and its complex conjugate gives:
[tex]Z*Z' = a^2 + b^2[/tex]
Now, of you look at option D, you can see we have the product of a number and its conjugate, then we can write the product and use the above rule to get:
[tex](x + i\sqrt{3} )*(x - i\sqrt{3} ) = x^2 + (\sqrt{3} )^2 = x^2 + 3[/tex]
Which is what we wanted to get, so that is the correct option.
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the tens digit of a 2 digit number is 5 greater than the units digit if you subtract twice the reverse number the result is one fourth the original
Answer:
The original number is 72.
Step-by-step explanation:
Let the number by
[A][B]
The reverse number is
[B][A]
Original number:
A = B + 5
[A][B] - 2[B][A] = [A][B]/4
10A + B - 20B - 2A = (10A + B)/4
8A - 19B = (10A + B)/4
32A - 76B = 10A + B
22A - 77B = 0
22(B + 5) - 77B = 0
22B + 110 - 77B = 0
-55B = -110
B = 2
A = B + 5 = 2 + 5 = 7
The original number is 72.
The reverse is 27.
Let's check.
"the tens digit of a 2 digit number is 5 greater than the units digit"
7 is 5 greater than 2,so 72 looks good so far.
"if you subtract twice the reverse number the result is one fourth the original"
The reverse number is 27. Twice 27 is 2 × 27 = 54.
Subtract 54 from 72: 72 - 54 = 18
18 is 1/4 of 72. It works.
Answer: the original number is 72
Use matrices to solve the system of equations if possible. Use Gaussian elimination with back substitution or gauss Jordan elimination. -x+y-z=-20,2x-y+z=29, 3x+2y+z=29
In matrix form, the system is given by
[tex]\begin{bmatrix} -1 & 1 & -1 \\ 2 & -1 & 1 \\ 3 & 2 & 1 \end{bmatrix} \begin{bmatrix} x \\ y \\ z \end{bmatrix} = \begin{bmatrix} -20 \\ 29 \\ 29 \end{bmatrix}[/tex]
I'll use G-J elimination. Consider the augmented matrix
[tex]\left[ \begin{array}{ccc|c} -1 & 1 & -1 & -20 \\ 2 & -1 & 1 & 29 \\ 3 & 2 & 1 & 29 \end{array} \right][/tex]
• Multiply through row 1 by -1.
[tex]\left[ \begin{array}{ccc|c} 1 & -1 & 1 & 20 \\ 2 & -1 & 1 & 29 \\ 3 & 2 & 1 & 29 \end{array} \right][/tex]
• Eliminate the entries in the first column of the second and third rows. Combine -2 (row 1) with row 2, and -3 (row 1) with row 3.
[tex]\left[ \begin{array}{ccc|c} 1 & -1 & 1 & 20 \\ 0 & 1 & -1 & -11 \\ 0 & 5 & -2 & -31 \end{array} \right][/tex]
• Eliminate the entry in the second column of the third row. Combine -5 (row 2) with row 3.
[tex]\left[ \begin{array}{ccc|c} 1 & -1 & 1 & 20 \\ 0 & 1 & -1 & -11 \\ 0 & 0 & 3 & 24 \end{array} \right][/tex]
• Multiply row 3 by 1/3.
[tex]\left[ \begin{array}{ccc|c} 1 & -1 & 1 & 20 \\ 0 & 1 & -1 & -11 \\ 0 & 0 & 1 & 8 \end{array} \right][/tex]
• Eliminate the entry in the third column of the second row. Combine row 2 with row 3.
[tex]\left[ \begin{array}{ccc|c} 1 & -1 & 1 & 20 \\ 0 & 1 & 0 & -3 \\ 0 & 0 & 1 & 8 \end{array} \right][/tex]
• Eliminate the entries in the second and third columns of the first row. Combine row 1 with row 2 and -1 (row 3).
[tex]\left[ \begin{array}{ccc|c} 1 & 0 & 0 & 9 \\ 0 & 1 & 0 & -3 \\ 0 & 0 & 1 & 8 \end{array} \right][/tex]
Then the solution to the system is
[tex]\boxed{x=9, y=-3, z=8}[/tex]
If you want to use G elimination and substitution, you'd stop at the step with the augmented matrix
[tex]\left[ \begin{array}{ccc|c} 1 & -1 & 1 & 20 \\ 0 & 1 & -1 & -11 \\ 0 & 0 & 1 & 8 \end{array} \right][/tex]
The third row tells us that [tex]z=8[/tex]. Then in the second row,
[tex]y-z = -11 \implies y=-11 + 8 = -3[/tex]
and in the first row,
[tex]x-y+z=20 \implies x=20 + (-3) - 8 = 9[/tex]