Ernesto tried to determine the solution for the system of equations using substitution. His work is shown below. x – y = 7 3x – 2y = 8 Step 1: x = y + 7 Step 2: 3(y + 7) – 2y = 8 Step 3: 3y + 7 – 2y = 8 Step 4: y + 7 = 8 Step 5: y = 1 In which step did Ernesto make the first error?

Answers

Answer 1
x - y = 7...x = y + 7
3x - 2y = 8

3(y + 7) - 2y = 8 ...correct
3y + 21 - 2y = 8 <== here is the error...did not distribute correctly

answer is : step 3

Answer 2

Answer:

answer C

Step-by-step explanation:



Related Questions

Janet's Junk Shop is having its annual sale. Matt wants to buy a mixer that originally sold for $28.62 and is now on sale for off. Matt also has a coupon for an additional 15% off the discounted price.

How much will Matt pay for the mixer?

Answers

[tex]n\% \:\:off = (100 -n)\% \:\: of \:the\: original \:price[/tex]
[tex]FinalPrice =[/tex]
[tex](Original Price \times(\frac{100\% - Discount}{100\%}))\times(\frac{100\% - Discount_2}{100\%}) =[/tex]
[tex]\big(\$28.62\times(\frac{100\% - 25\%}{100\%})\big) \times(\frac{100\% - 15\%}{100\%}) = [/tex]
[tex]\big(\$28.62\times(\frac{3}{4})\big) \times(\frac{17}{20}) \approx \$18.25[/tex]

Matt will pay [tex]\$18.25[/tex] for the mixer

What are the fractions of 48

Answers

Alright, so 48/1=48, 48/2=24, 48/3=16, 48/4=12, 48/5= none, 48/6=8, and 48/7=none. As 7^2 = 49 is higher than 48, there are no more numbers to be able to find as they will return a factor already stated. The factors are 1, 48, 2, 24, etc..

Evaluate the following expression.

5-3

Answers

subtract 5-3 = 2


check 2+3 =5

How long is a football field

Answers

a football field is 360 feet 

the distance between goal lines is 100 yards, each end zone is 10 yards

 so total length of a football field is 120 yards

A machine factory produces 2 parts per second. One shift is 10 hours long. What is the production rate in parts per shift?

Answers

60 seconds per minute

 2 x 60 = 120 parts per minute

60 minutes per hour

120*60 = 7200 parts per hour

7200 x 10 hours = 72,000 parts per 10 hour shift

whats the property in equation 3(2x-6)=6x-18

Answers

3(2x-6)=6x-18

Distributive property

hope it helps
distributive because the 3 is distributing itself in the 2x and the -6

Solve x3 = 1 over 8.

Answers

x^3=1/8

x=(1/8)^(1/3)

x=1/2

Answer:

The simplified form of the provided equation is 1/2.

Step-by-step explanation:

Consider the provided equation.

[tex]x^3=\frac{1}{8}[/tex]

8 can be written as 2³

1 can be written as 1³

Therefore the provided equation can be written as:

[tex]x^3=\frac{1^3}{2^3}[/tex]

[tex]x^3=(\frac{1}{2})^3[/tex]

[tex]x=\frac{1}{2}[/tex]

Hence, the simplified form of the provided equation is 1/2.

The solution to the system of equation below is (−2, −1).

2x − 3y = −1
11x − 9y = −13

When the first equation is multiplied by −3, the sum of the two equations is equivalent to 5x = −10.

Which system of equations will also have a solution of (−2, −1)?


5x = −10
11x − 9y = −13


2x + 9y = −1
11x − 9y = −13


−6x + 9y = −1
11x − 9y = −13


−6x + 3y = −1
5x = −10

Answers

5x=-10
11x-9y=-13

5x(-2)=-10
11x(-2)-9x(-1)=-13

Answer:

The correct option is 1.

Step-by-step explanation:

If a system of equation have solution (a,b), then the equations of system must be satisfied by the point (a,b).

It is given that the system of have solution (-2,-1), so the equations of system  must be satisfied by the point (-2,-1).

The system of equation in option 1 is

[tex]5x=-10[/tex]

[tex]11x-9y=-13[/tex]

Put (-2,-1) in the above equations.

[tex]5(-2)=-10\Rightarrow -10=-10[/tex]

[tex]11(-2)-9(-1)=-13\Rightarrow -13=-13[/tex]

Since left hand side is equal to right hand side, therefore the point (-2,-1) satisfy the equations and (-2,-1) is the solution of the given system.

Similarly check the other system of equations, whether the point (-2,-1) stratify the equations or not.

In option 2,

[tex]2x+9y=-1[/tex]

[tex]2(-2)+9(-1)=-1\Rightarrow -13=-1[/tex]

Since left hand side is not equal to right hand side, therefore the point (-2,-1)  is not the solution of this system of equation.

In option 3,

[tex]-6x+9y=-1[/tex]

[tex]-6(-2)+9(-1)=-1\Rightarrow 3=-1[/tex]

Since left hand side is not equal to right hand side, therefore the point (-2,-1)  is not the solution of this system of equation.

In option 4,

[tex]-6x+3y=-1[/tex]

[tex]-6(-2)+3(-1)=-1\Rightarrow 9=-1[/tex]

Since left hand side is not equal to right hand side, therefore the point (-2,-1)  is not the solution of this system of equation.

Only option 1 is correct.

Write 0.8 repeating as a fraction

Answers

The answer is 8/9 i believe.

Answer: 8/9

Step-by-step explanation: I got the answer right

A gift box is a rectangular prism14inches long,5inches wide,and 4inches high.If the box is to be covered in fabric ,how much fabric is needed if there is no overlap?

Answers

that's the surface area

when he length=L
width=W
and height=H


SA=2(LW+WH+LH)
so
L=14
W=5
H=4

subsitute
SA=2((14)(5)+(5)(4)+(14)(4))
SA=2(70+20+56)
SA=2(146)
SA=292

you need 292 square inches of fabric

The total fabric needed would be 292 square inches.

To calculate how much fabric is needed to cover the gift box without overlap, we must find the surface area of the rectangular prism representing the box. The formula to find the surface area of a rectangular prism is 2lw + 2lh + 2wh, where l represents the length, w represents the width, and h represents the height.

Given the dimensions of the box are 14 inches (length), 5 inches (width), and 4 inches (height), we calculate the surface area as follows:

2 (14 × 5) = 2 × 70 = 140 square inches (for the top and bottom)2 (14 × 4) = 2 × 56 = 112 square inches (for the front and back)2 (5 × 4) = 2 × 20 = 40 square inches (for the left and right sides)

The total surface area is 140 + 112 + 40 = 292 square inches of fabric needed to cover the entire box.

Triangle XYZ is reflected across the line y=x and X'= (2, -15). What are the coordinates of X,?

Answers

if reflected coordinate is (2,-15) , it mean coordinates` x and y values are changed. So, if you want to know X, reflect once again! 
Answer: (-15,2)

Answer:

the answer to this is A

Step-by-step explanation:

i need help on this math problem

Answers

Mean is sum/number of values
10+11+12+12+14+15+15+15=104
104/8=13
Final answer: 13

3(x+1)-[2(3-2x)-3(3-x)]

Answers

Distributive property
3x+3-2-3x+9
Combine like terms
0x+3-2+9
X=10

Sam bought 86 pounds of flour for his bakery. Every day he used the same amount of flour to make bakery items. After 10 days, Sam was left with 25.2 pounds of flour. On average, how many pounds of flour did Sam use each day?

Answers

86-25.2 = 60.8 pounds of flour used

60.8/10 = 6.08 pounds used per day

Answer:

6.08

Step-by-step explanation:

first, i subtracted 86 from 25.2 to get what he used in the 10 days, which was 60.8, then i would divide it by 10 bc of 10 days to get 6.08. Hope this helps!

What is tan 45 degrees

Answers

Tan 45* = one

If this helps please give brainliest ;)

Answer:

tan 45°= 1

Step-by-step explanation:

you find the opposite/adjacent= 1

scientific notation of 19 hundred thousandths

Answers

Answer
1.9×〖10〗^(-4)

Explanation
A number is said to written in scientific notation when it is in the form A×〖10〗^n, where 1≤A<10 and n is an integer.
In this case,
19 hundred thousandths =19/100,000=0.00019
0.00019=1.9×〖10〗^(-4)
19 hundred thousandths to scientific notation = 1.9×〖10〗^(-4) 

Final answer:

The scientific notation of 19 hundred thousandths (0.0019) is 1.9 × 10⁻³, accomplished by moving the decimal point three places to the right.

Explanation:

The scientific notation of the number 19 hundred thousandths, which is written as 0.0019 in decimal form, involves expressing it as the product of a number between 1 and 10 and a power of 10. To convert to scientific notation, we must move the decimal point three places to the right, which will change the number to 1.9. Since we moved the decimal point to the right, the exponent will be negative. Therefore, 0.0019 in scientific notation is 1.9 × 10⁻³.

If a scale model of a building is 5 inches wide by 7inches long. if the scale is 1 in.:15ft,how long is the building?

Answers

So if the scale is one 1in:15ft then for every inch on the model is 15 feet for the actual building so 7*15 should be the length so if I'm not being stupid the building is 105 feet long.

If a scale model of a building is 5 inches wide by 7inches long then the real-life length of the building is 105 feet.

What is Unit of Measurement?

A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity.

If the scale of the model is 1 inch : 15 feet, this means that every inch on the model represents 15 feet in real life.

The model is 5 inches wide by 7 inches long.

Let's use the length dimension to find the real-life length of the building:

7 inches on the model represents 7 x 15 = 105 feet in real life.

Therefore, the real-life length of the building is 105 feet.

To learn more on Unit of Measurement click:

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1/2x =20

Pls help
I need answer in like a minute

Answers

if ya meant like [tex]\frac{1}{2}x=20[/tex]
multiply both sides by 2/1 to get x=40

if ya meant like [tex]\frac{1}{2x}=20[/tex]
multiply both sides by x and divide both sides by 20 to get [tex]x=\frac{1}{40}[/tex]

depends which one it is

A car company tested a sports car on a road with different inclines. The test driver tested the car by driving a distance of x miles on a flat road, (x2 + 3) miles downhill, and (x − 7) miles uphill. Which simplified expression is equivalent to the total distance, in miles, for which the car was tested?

Answers

The answer is x= -4 if that's what they asking for

C. x²+ 2x - 4 Should be your answer to this question.

Gavin agrees to buy a 6-month package deal of monthly gym passes and in turn receives a 15% discount. Write an algebraic expression to represent the total cost of the monthly passes with the discount, if x represents the cost of each monthly pass.

Answers

6*x=y
15%*y=Z
that is the equations

Tickets to a concert cost 2$ for children and 5$ for adults. If 630 people attended the concert and ticket sales totaled 2,910$, how many children attended the concert

Answers

Look I only searched the answer but here it is.
80 childrens tickets and 550 adults tickets were sold.

c= children

a= adults

c+a = 630

c=630-a

2c + 5a = 2910

2(630-a) +5a=2910

1260-2a+5a=2910

1260+3a=2910

3a=1650

a = 1650/3=550

550 adult tickets

630-550 = 80 children's tickets


check:

550*5 = 2750

80*2=160

2750+160=2910

The graph shows the height, y, in centimeters, of a plant after a certain number of weeks, x. Shania drew the line of best fit on the graph.

A graph titled Plant Height shows Number of Weeks on x axis and Height of Plant in cm on y axis. The scales on both x and y axes are shown from 0 to 5 at increments of 5. The graph shows dots at the ordered pairs 0, 1 and 0.5, 1.2 and 1, 1.4 and 1.5, 2 and 2, 2.4 and 2.5, 2.7 and 3, 3 and 3.5, 3.3 and 4, 3.5 and 4.5, 3.8 and 5, 4. A straight line joins the ordered pairs 0, 1 and 5, 4

What would most likely be the approximate height of the plant after 7 weeks?

5.2 centimeters
7.6 centimeters
8.7 centimeters
12.7 centimeters

Answers

You are given a a graph titled Plant Height that shows Number of Weeks on x axis and Height of Plant in cm on y axis. Plotting this and you will get an equation of y = 1.2792x - 0.1665 (I used excel using the given points from the above problem).

y = 1.2792x - 0.1665
y = 1.2792 (7) - 0.1665
y = 8.78 centimeters.

The most likely approximate height of the plant after 7 weeks is 8.7 centimeters.

Answer:

5.2 cm.

Step-by-step explanation:

Given :

Number of Weeks(x)     Height of Plant (y)

 0                                          1

0.5                                       1.2

  1                                         1.4

 1.5                                       2

  2                                        2.4

 2.5                                      2.7

  3                                        3

 3.5                                      3.3

  4                                        3.5

 4.5                                      3.8

  5                                         4

We are given that A straight line joins the ordered pairs 0, 1 and 5, 4

So, we will find the equation of line using two point slope form:

[tex]y-y_1=\frac{y_2-y_1}{x_2-x_1}(x-x_1)[/tex]

[tex](x_1,y_1)=(0,1)[/tex]

[tex](x_2,y_2)=(5,4)[/tex]

Substitute the values in the formula

[tex]y-1=\frac{4-1}{5-0}(x-0)[/tex]

[tex]y-1=\frac{3}{5}(x)[/tex] ---A

Now we are supposed to find e the approximate height of the plant after 7 weeks.

Substitute  x = 7 in A

[tex]y-1=\frac{3}{5}(7)[/tex]

[tex]y=\frac{3}{5}(7)+1[/tex]

[tex]y=5.2[/tex]

Hence  the approximate height of the plant after 7 weeks is 5.2 cm.

sharon and anthony dropped a stone from a 150-foot cliff. find the time, t, in seconds that it will take for the stone to reach the ground. let t=1/4 square root of s, where s represents the distance in feet the stone will fall.

Answers

Work:
(s = 150ft
t = 1/4 square root of s)
Square Root (150) = 12.2474487139
12.2474487139 ÷ 4 = 3.0618621785 = ~3.062

Final Answer: About 3.062 seconds.

A bag has 6 yellow marbles and 6 brown marbles. Half of the brown marbles are made of glass. A marble is selected at random from the bag. What is the probability that it is a brown, glass marble?

Write your answer as a fraction in simplest form.

Answers

total = 12 marbles
6 brown marbles but half of the brown marbles are made of glass
so brown and made of glass = 3
probability that it is a brown, glass marble = 3/12 = 1/4

answer
1/4

Which undefined term is needed to define a circle

Answers

The undefined term 'point' is needed to define a circle

Answer:

the first one is "point" and the second is "1/2"

Step-by-step explanation:

The scores of several classmates on a language arts test are shown below: 86 points 87 points 87 points 94 points 95 points 82 points 78 points 89 points 80 points 84 points What is the median score for these students?

Answers

78,80,82,84,86,87,87,89,94,95
86+87/2 = 86.5

Answer:

78,80,82,84,86,87,87,89,94,95

86+87/2 = 86.5

Step-by-step explanation:

Margie calculated that she would spend $175 on school supplies this year. She actually spent $97.50 on school supplies. What is Margie’s percent of error? 77.3% 79.5% 44.2% 4.4%

Answers

175 - 97.5 = 77.5

77.5  /  97.5 = 0.7948 = 79.5%

answer

79.5%

Margie’s percent of error is 79.5%.

First step is to calculate the amount that Margie was off by

Amount=$175 - $97.50

Amount=$77.5

Second step is to find Margie percent of error  

Percent of error=77.5 / 97.50× 100

Percent of error = 79.48717949%

Percent of error=79.5% (Approximately)

Inconclusion Margie’s percent of error is 79.5%.

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Which of the fractions shown has the greatest value?

2/4

4/7

1/3

4/9

Answers

4/7 has the greatest value; it is .57
1/2= .5
1/3=.33
4/9 = .44

Answer:

4/7 has the greatest value; it is .57

Step-by-step explanation:

What is the midpoint of the line segment with endpoints (1,6) and (-3,4)?

Answers

The midpoint of a segment with endpoints (1,6) and (-3,4) is (-1,5)
hope this helps:)
please mark thanks and brainliest:)
to find the midpoint add 1 and -3 and divide it by two. thats your answer for x-axis

add 6 and 4 and divide the answer by 2 and you will get the answer for y-axis.

therefore,
midpoint = ( (1 + -3) ÷ 2 , (6+4) ÷ 2 )
= ( -2 ÷ 2 , 10 ÷ 2 )
= (-1, 5)

How do you find the LCM???

I know that I asked how to find the LCM of 8 and 9 but I don't know what to multiply by to get it.

Answers

If you know the LCM then you divide it by the other number.
If you don't already know it: is 8 a factor of 9 or do they have equal factors? No.
Is 9 a factor of 8 or do they have equal factors? No.
The easy way: multiply 8 by 9 to get LCM :)
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