Question

Select the system of equations that corresponds to the given graph.
a. -2x - y = 4
2x + y = -2

b. -8x + 4y = -16
-4x + 2y = -8

c. x - 2y = 6
-2x + y = 4

d. x + 3y = 9
3x + 2y = 4

Answer 1

A is wrong.

Those lines in choice A are parallel.

Answer 2

B is also wrong. Both those equations are the same.

Answer 3

The answer is D.

I graphed all of them here: https://www.desmos.com/calculator

Answer 4

For the following system, if you isolated x in the first equation to use the Substitution Method, what expression would you substitute into the second equation?

-x - 2y = -4
3x + y = 12

Choose one answer.
a. -2y - 4
b. 2y - 4
c. 2y + 4
d. -2y + 4

Answer 5

Wait hold on..

Answer 6

\(-x - 2y = -4\)
\(-x = 2y - 4\)
(x = -2y + 4\)

Answer 7

So your answer is D.

Answer 8

how did you do that?

Answer 9

Well if you're going to input 'x' into the second equation, the first equation must have an 'x -'. So I just re-arranged the terms, AND multiplied each term by ‘-1’ to get rid of the negative sign on ‘x’.

Answer 10

What is the value of the x variable in the solution to the following system of equations?
2x + 3y = 4
x - 2y = -5

Choose one answer.
a. 2
b. -2
c. 1
d. -1

Answer 11

can you do step by step with me for the next one? @iGreen

Answer 12

k

Answer 13

Just copy and paste the equations into separate boxes on the right in this graphing calculator: https://www.desmos.com/calculator. Look for where they intersect, then you have your answer.

Answer 14

Did you get the answer?

Answer 15

I just dont understand how to read the graph. I put my equation in tho.

Answer 16

The place where the two lines intersect is the solution! So what is the point where the two lines intersect?

Answer 17

They didnt intersect -.- so no solution?

Answer 18

They DID.

Answer 19

Let's just substitute instead.

Answer 20

Okayy

Answer 21

Substitute:

\(2x + 3y = 4\)
\(x - 2y = -5\)

Get ‘x’ on one side of the equation, then we can input it into the first.

Add 2y to both sides:

\(x = 2y – 5\)

Okay now we can input \(‘2y – 5’\) into \(‘2x + 3y = 4’\).

\(2x + 3y = 4\)
\(2(-2y – 5) + 3y = 4\)

Solve for \(‘y’\):

\(2(-2y – 5) + 3y = 4\)
\(-4y – 10 + 3y = 4\)
\(-4y + 3y = 14\)
\(-y = 14\)
\(y = -14\)

Answer 22

Oh forget it, I did something wrong.

You graph it in Desmos, you get (-1, 2) for your solution.

Answer 23

What is the value of the y variable in the solution to the following system of equations?
5x + 3y = 7
3x - 5y = -23

Answer 24

a. -1
b. 1
c. -4
d. 4

Answer 25

A

Answer 26

Which point lies in the solution set for the following system of inequalities?
y < 2x + 4
y < -2x + 2

Answer 27

a. (1, 0)
b. (-5, -2)
c. (0, -3)
d. (-1, 5)

Answer 28

C

Answer 29

Solve the following system of equations. Please show your work to receive full credit.
x - y = 10
2x + y = 2

Part 2:
Explain which method you chose to solve the system and why you felt it was the best choice.

Answer 30

Substitute:

x – y = 10
x = 10 + y

Input into other equation:

2x + y = 2
2(10 + y) + y = 2
20 + 2y + y = 2
20 + 3y = 2
3y = -18
y = -6

Input ‘y = -6’ into any equation:

x – y = 10
x – (-6) = 10
x + 6 = 10
x = 4


So the solution is (4, -6).

Answer 31

Part 2:

Just say something like:

"Part 2: I chose the substitution method, and I chose this because I thought it was the easiest method."

Answer 32

Thank you!