A student solved a system of equations by elimination. The answer is not correct. Describe the error in the solution.

Original Problem:

3x−2y=8

x+y=2

Student Work:

3x−2y=8

2x+2y=2

5x=10

x=2

Answers

Answer 1

The student went from x+y = 2 to 2x+2y = 2, which is not correct. They multiplied the left side by 2, but forgot about the right hand side.

They should have gone from x+y = 2 to 2x+2y = 4 after multiplying both sides by 2.

So they should have this new equivalent system

[tex]\begin{cases}3x-2y = 8\\2x+2y = 4\end{cases}[/tex]

Add straight down and we end up with the new equation 5x = 12 which solves to x = 12/5 = 2.4

Use that x value to solve for y. You should get y = -2/5 = -0.4


Related Questions

Can someone help me on these two questions? NO LINKS!

Answers

Answer:

6. a   7. c

Step-by-step explanation:

6. 72 is multiple of 24 and has 18 as a factor

7. 56= 32= 88

   8(7+ 4)

=) 56+ 32= 88

OR

=) 8(11)= 88

It would be…
56+32=88
8(11)=88

How to solve this? If u can ols sho step by step

Answers

for example, the line is y = ax + b (1)

we have the line go through the point ( 0 ; 3 ) so y = 3 (2)

we also have the line go through the point ( 0 ; 5 ) so x = 5 (3)

And look at the picture we also have b= 3 (4)

Put (2)(3)(4) in (1) we gonna have  a= -3/5

so the line gonna be y = -3/5x + 3

P/s: if you don't understand,  you can try this:

we have the line go through the point ( 0 ; 3 ) so y = 3

we also have the line go through the point ( 0 ; 5 ) so x = 5

so put it in the answer :

+) -3x -5y = 15

when x = 0 => y = -3 but y = 3 so it's wrong

+) y = -3/5x + 3

when x = 0 => y = 3

when y = 0 => x = 5  it's right :))

+) 3x + 5y = 15

when x = 0

when y = 0 => x = 5 it's right :)) but write improperly :'))

+) y = -3/5 ( x - 5 )

when x = 0 => y = 3

when y = 0 => x = 5 it's right :)) but write improperly :'))

so we choose y = -3/5x + 3

ok  done. Thank to me :>

Can some one help me solve this

Answers

Hello mashiamcphee141!

Let's solve for x in the given question.

[tex]\sf\:\frac { x + 3 } { 2 } + \frac { 2 x } { 7 } = 7\\\sf\:7\left(x+3\right)+2\times 2x=98 \\\sf\:7x+21+2\times 2x=98 \\\sf\:11x+21=98 \\\sf\:11x=98-21 \\\sf\:11x=77 \\\sf\:x=\frac{77}{11} \\\boxed{\sf\:x=7 }[/tex]

Steps :-

At first, multiply both sides of the equation by the LCM = 14.Now, simplify the equation using distributive property & other operations. We'll get the value of 'x' as 7.

See the attachment if the working is not clear.

____________

[tex]\mathfrak{Lucazz}[/tex]

Given that:

[{(x+3)/2} + (2x/7)] = 7

Take the LCM of 2 and 7 is 14.

⇛[{7(x+3)+2(2x)}/14] = 7

⇛[{7x+21 + 4x}/14] = 7

⇛[{11x+21}/14] = 7/1

Now,

By using cross multiplication method,we get

⇛1(11x+21) = 7(14)

⇛11x + 21 = 58

⇛11x = 58-21

⇛11x = 37

∴ x = 37/11

Hence, the value of x will be 37/11 respectively.

also read similar Questions:- 2(x+1)+3=7 how do I solve this? Is this correct? 2(x+1)+3=7 2x + 2 +3=7 2x+2 +3=7 2x+5=7 -5 7 2x= 2 2 2 x=1...

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Solve the equation- [tex] \frac{5}{x - 3} - \frac{4}{x + 4} = \frac{1}{x} [/tex] He…

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ahh i need help with these 2 questions ill mark u as brainliest ​

Answers

Answer:

3. x = 96

4. x = 6

Step-by-step explanation:

1. John is going to join a gym. He must pay a one-time membership fee of $75 and a monthly fee of $30. Let m = the number of months John has his membership. Write an expression to represent this situation How much will John pay for 6 months of membership?

2. Madison is having a party. She went to the store and bought a cake for $18.50 and 20 balloons. Her total bill was $63.50. How much did each balloon cost if they all cost the same? Write and solve an equation. Please look over these again. Webmail your answers to get your points back.

Answers

John's membership in the gym and Madison's party are illustrations of linear equations.

1. John's equation

The given parameters are:

[tex]\mathbf{Base = 75}[/tex]

[tex]\mathbf{Monthly = 30}[/tex]

The monthly expression is:

[tex]\mathbf{f(m) = Base + Monthly \times m}[/tex]

So, we have:

[tex]\mathbf{f(m) = 75+ 30 \times m}[/tex]

[tex]\mathbf{f(m) = 75+ 30m}[/tex]

For 6 months, we have:

[tex]\mathbf{f(6) = 75+ 30 \times 6}[/tex]

[tex]\mathbf{f(6) = 255}[/tex]

Hence, the expression that represents the situation is [tex]\mathbf{f(m) = 75+ 30m}[/tex], and the amount for 6 months of membership is $255

2. Madison's party

The given parameters are:

[tex]\mathbf{Cake = 18.50}[/tex]

[tex]\mathbf{Balloon = 20}[/tex]

[tex]\mathbf{Total = 63.50}[/tex]

Let n represent the cost of each balloon.

So, the equation is:

[tex]\mathbf{Cake + Balloon \times n = Total}[/tex]

This gives:

[tex]\mathbf{18.50 + 20 \times n = 63.50}[/tex]

Subtract 18.50 from both sides

[tex]\mathbf{ 20 \times n = 45}[/tex]

Divide both sides by 20

[tex]\mathbf{ n = 2.25}[/tex]

Hence, the expression that represents the situation is [tex]\mathbf{18.50 + 20 \times n = 63.50}[/tex], and the cost of each balloon is $2.25

Read more about linear equations at:

https://brainly.com/question/11897796

Five years ago, a father was 3 times as old
as his son, now their combined ages amount
to 110 years. How old are they?

Answers

Answer:

Father is 80 years old and the son is 30

Step-by-step explanation:

Let father be x and son be y:

x-5 = 3(y-5)

x = 3y-10 ------ eq1

x+y = 110

x = 110 -y -------- eq2

Now if we combine the 2 equations we get:

3y + y = 110+10

y=30 (sons age)

Substituting in equation 2 we get:

x = 110 - 30

x = 80

Therefore, the fathers age is 80 and the sons age is 30.

PLZ HELP ME!!!!!!!!!!!!!!!!!!!!!!

Answers

Answer:

i have no idea what this question is asking for but my guest is that you need to reformate the equations

-5x+y=-11 in y+mx+b format is y=5x-11

x-y=7 in y=mx+b formate is y=-x+7

Help !! I don’t understand

Answers

Answer: .8, -.9, -.5, .9 (estimates)

Step-by-step explanation: correlation coefficients are between -1.0 and 1.0.

    -1.0 means a perfectly negative correlation, which will be a straight line going down from left to right

    0 means no correlation, it's just random points on the graph with no sense of direction or relationship

   1.0 means a perfectly positive correlation, which will be a straight line going up from left to right

the more line-like the shape the data points make are, the further away the correlation coefficient is from 0. you can tell if it's negaitive or positive from the direction of the line.


The data points in the table show minutes on phone calls Identify the missing values in the table.
per day, x, and text messages sent per day, y. The least-
squares regression line for the data is j = 100 - 0.5x.
Use this table to answer the question.
A=
B=
C =
D =

Answers

Answer:

A= 5

B= 0

C= 50

D= -5

Step-by-step explanation:

Just did it on EDGE

Can someone help me. All i need o know is what is the value after 10 years i done the equation part by myself
NO BOTS OR ILL REPORT YOU!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1
ILL GIVE BRAINLY TO CORRECT ANSWER
100 points

Answers

Answer:

$4811

Step-by-step explanation:

Initial price = 35,000

18% decrease anually = 18/100 = -0.18

after 10 years

substitute these values in the formula shown in below figure

A = 35000 * ( 1 + -0.18/1  ) ^10

= 35000 * 0.82^10

= 4,810.681

= $4811

Six apples and three oranges cost $3.36. Two apples and five oranges cost $3.04. Find the cost of one apple and the cost of an orange.

Answer and step-by-step explanation pls!!

Answers

Answer:

$0.8

Step-by-step explanation:

let x represent the price of apples

let y represent the price of oranges

6x+3y=3.36—eqn 1

2x+5y=3.04—eqn 2

Multiply eqn 2 by 3

3(2x+5y=3.04)=6x+15y=9.12

Subtract eqn 2 from 1

6x+3y=3.36

-{6x+15y=9.12}

-12y=-5.76

y=0.48

plug y=0.48 into eqn 1

6x+3(0.48)=3.36

6x=3.36-1.44

x=1.92/6=0.32

That is, an apple costs $0.32 and an orange costs $0.48

Therefore the cost of an orange and an apple=$0.48+$0.32=$0.8

Answer:

apple: $0.32orange: $0.48

Step-by-step explanation:

Let x and y represent the costs of 1 apple and 1 orange, respectively. The two cost figures tell us ...

  6x +3y = 3.36

  2x +5y = 3.04

We note that all of the numbers in the first equation are divisible by 3, so we can divide by 3 to reduce it to ...

  2x +y = 1.12

Subtracting this from the second equation gives ...

  (2x +5y) -(2x +y) = (3.04) -(1.12)

  4y = 1.92 . . . . . . . simplify

  y = 0.48 . . . . . . . divide by 4

Then the cost of an apple can be found from our reduced equation:

  2x +0.48 = 1.12 . . . substitute for y

  2x = 0.64 . . . . . . . . subtract 0.48

  x = 0.32 . . . . . . . . . divide by 2

The cost of one apple is $0.32; the cost of one orange is $0.48.

_____

Additional comment

The method of solution we used here is called "elimination," because the x-variable was eliminated from the combined equations. There are numerous other methods available for solving a system of linear equations. Most graphing calculators have features for graphing and for reducing matrices that will solve these for you. All you need to do is enter the equations.

34.98+12.24=?
answers please​

Answers

Answer:

Hello!

After reading your question I have calculated the correct answer to be:

47.22

Step-by-step explanation:

The way I solved this equation was I first split the equation into two parts.

I took the two whole numbers, being "34" and "12", and made their own equation:

"34+12=?"

And then I took the two partial numbers "0.98" and "0.24" and made their own equation:

"0.98+0.24=?"

I then solved both equations:

"34+12= 46"

"0.98+0.24= 1.22"

And added those two solutions together to come up with the final solution:

"46+1.22= 47.22"

Hope this helped!

Answer:

47.22 is the answer

Step-by-step explanation:

hope it helps you

100 POINTS!! WILL MARK BRAINLIEST
NEED RESPONSE ASAP PLEASE AND THANK YOU!!

A feasible region is bounded by the constraints:
y ≤ 20-x
{ y ≥ 20-4x
y ≥ 5-0.25x

The objective function is P = 3x + 5y.

(a) Graph the feasible region.
(b) Find the value of the objective function at each vertex of the feasible region.
(c) What is the minimum value of the objective function, P?
(d) At which vertex point does the minimum value occur?
Show all work.

Answers

Answer:

1) b. at vertex ( 0,20) P = 5(20) = 100 at vertex ( 4,4) P = 3(4) + 5(4) = 32 at vertex (20,0) P = 3(20) = 60 c. x = 4 , y = 4 2) x-intercepts x 1 = 1.66667, ...

Step-by-step explanation:

Determine the measure of angle ∠ABD.

a) 48
b) 12
c) 90
d) 24

Answers

Answer:

24 or 12

Step-by-step explanation:

simplify 6(x+3-2) (4-x)

Answers

The answer is -6^2-6x+120

what is the value of x?
a)
[tex]2 \sqrt{10} [/tex]
b)
[tex]2 \sqrt{2} [/tex]
c)
[tex]2 \sqrt{5} [/tex]
d)
[tex]2 \sqrt{3} [/tex]

Answers

Answer:

A

Step-by-step explanation:

using pythagoras theorem

h²=p²+b²

Four integers have a mean of 12, a median of 12, a mode of 12 and a range of 6.

Find the four integers.

Answers

the four integers can possibly be 4,8,10,2

Choc-Arcade has Miguel's two favorite things: a chocolate shop and an arcade! Not only that, but Choc-Arcade's loyalty program rewards Miguel with free game tokens every time he buys chocolates. He gets 4 free game tokens for each chocolate he buys. There is a proportional relationship between the number of chocolates Miguel buys, x, and the number of free game tokens he gets, y.

Answers

Answer:

x : 4y

Step-by-step explanation:

For every one chocolate he buys, he gains 4 free game tokens

(PLEASE HELP, THIS IS DUE TONIGHT!!!!) 2. If triangle ABC is congruent to triangle DEF by SAS, AB=DE, information that shows SAS?

3. In quadrilateral ABCD, AB and CD are parallel and congruent, BC and DA are parallel and congruent, and AC and BD are congruent. What type of figure is this and explain why you chose this figure?

Answers

Answer:

One pair of opposite sides are parallel and congruent. From the figure, one pair of opposite sides has the same measure and are parallel.

Help me on this pls and thank you

Answers

Answer:

5x - 15 + 2x + 90 = 180

180 since it's a flat line, and all the angles should add up to 180 which is angle AOB, 90 degrees is already given in the middle.

Simplify all the terms (The algebra portion)

7x - 15 + 90 = 180

7x + 90 = 195

7x = 105

x = 105/7

x = 15

now substitute in x for all these angles

2(15) = 30 degrees is the angle GOB

5(15) - 15 = 60 degrees is the angle AOF

60 + 90 + 30 = 180 degrees.

and x = 15

How can you tell if you are finished solving a polynomial division problem?

Answers

The polynomial division problem can be concluded finished if; their is no remainder or the Divisor is larger than the remainder.

According to the question:

We are required to determine when a polynomial division problem is finished.

In polynomials, the division of a polynomial NY the Divisor gIves a quotient and a remainder.

Read more:

https://brainly.com/question/12520197

someone plz help me!!!!!!!!!!!!!!

Answers

Step-by-step explanation:

In the given set of questions regarding the concept of division, it is important to understand the parts of a division problem.

Definitions:

In a division problem such as 15 ÷ 3 = 5:

15 represents the dividend, which is the number being divided into groups. 3 represents the divisor, which is the number of groups that divides the dividend.  5 represents the quotient, which is the result of dividing the dividend and the divisor. Solution:

Now that we have defined the parts of a division problem, we can proceed to matching the division problems to its corresponding representation of equal groups.

1.) 15 ÷ 3 = 5 "There are 5 equal groups of 3."  

If you multiply the quotient, 5, by the divisor, 3, it results in the dividend: 5 × 3 = 15. This occurs because multiplication is the opposite mathematical operation of division.  

2.) 45 ÷ 5 = 9 "There are 9 equal groups of 5."  

      9 equal groups of 5 = 9 × 5 = 45.

3.)   8 ÷ 4 = 2 "There are 4 equal groups of 2."  

      4 equal groups of 2 = 4 × 2 = 8.

4.) 18 ÷ 6 = 3 "There are 3 equal groups of 6."  

      3 equal groups of 6 = 3 × 6 = 18.

Find each indicated length if A is the midpoint of XZ and B is the midpoint of YZ (please help asap!!)

Answers

Answer:

Step-by-step explanation:

We have to think that the median and the side is parallel to are one small and one big, and that the small one is half of that big one and that the big one is the small one doubled.

AB = 8 ( the small one ) then XY = 2* 8 = 16 ( the big one)

AB = 3 then  XY = 2* 3 = 6

AB = 2.5 then XY = 2*2.4 = 5

XY = 18 ( the big one)  then AB = 18/2 = 9 ( the small one)

XY = 4 then AB = 2/2 = 2

XY = 9 then AB = 9/2 = 4.5

The length of the base of an isosceles triangle is x. The length of a leg is 2x-5 . The perimeter of the triangle is 25. Find x.

Answers

Answer:

=x+2x-5=25

=3x-5=25

=3x=30

=x=10cm

Step-by-step explanation:

mark as brainliast

Answer:

10 cm

Step-by-step explanation:

plz help! so hardddddddd

Answers

Answer: The average temperature on Earth has risen.

Step-by-step explanation:

If you look at the graph, you can see that the average for temperature on Earth has risen since 1800s through 2000s

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!7

Answers

Answer:

The answer is B final answer becuase its all positive.

0.011 divided by 0.25

Answers

Answer:

0•044 is the correct answer

Answer:

0.044

Step-by-step explanation:

Mary spent a total of $354.30 for a party. She spent $200.90 on food, plus an additional $30.68 for each hour of the party. How long was the party?

Answers

Answer:

About 5 hours

Step-by-step explanation:

Hope it helps

can you answer number four please

Answers

Answer:

l = 104/3

w = 40/3

Step-by-step explanation:

l = 2*w + 8

P = 2(l + w) = 96

48 = l + w

2w + 8 + w = 48

3w = 40

w = 40/3

l = 2*40/3 + 8

= 80/3 + 8

= 80 + 24  / 3

= 104/3

express the following as decimal. 25/1000
20/50
3/50
2/3​

Answers

Answer:

[tex]\frac{25}{1000}[/tex] = 0.025

[tex]\frac{20}{50}[/tex] = 0.4

[tex]\frac{3}{50}[/tex] = 0.06

[tex]\frac{2}{3}[/tex] = 0.(66) or 0.66666666666666666

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