Question

Choose the system of equations which matches the following graph. (GRAPH ATTACHED)

A. 5x - y = 7
2x + y = 0

B. 5x + y = -7
2x - y = 0

C. 5x - y = 7
2x - y = 0

D. 5x + y = -7
2x + y = 0

Answer 1

The one going down passes through the origin and must have a negative slope.

Answer 2

So it's form should be y = -nx, n being a constant, now let's see which one correspond to this

A. 5x - y = 7
2x + y = 0 -> y = -2x (looks good)

B. 5x + y = -7
2x - y = 0 -> y = 2x (That's not right)

C. 5x - y = 7
2x - y = 0 -> y = 2x (Not good)

D. 5x + y = -7
2x + y = 0 -> y = -2x (looks good)

Answer 3

We have A & D left, now, the one that's going up must have a positive slope, let's see:

A. 5x - y = 7 -> y=5x-7
2x + y = 0

D. 5x + y = -7 -> y = -7-5x -> y = -5x-7 (Negative slope, wrong)
2x + y = 0

So you are left with A :)

Answer 4

Thank you for actually showing how to do it along with the answer!