Question

The graph shows the solution to which system of equations?

Answer 1

So let's start by guesstimating the slopes:
the green line has a slope close to -x, but more negative than that, possibly -2; the pink line has a slope close to +x, but higher towards +2.

Next let's look at the solution: the two lines intersect at the point (1, -1).
**you could just simple plug that x (1) into all the equations, but let's rule out answers anyway. ;)

A) is incorrect because the slopes of -1 and +1 are off from out predicted -2 and +2
B) is incorrect because of a similar reason, the slopes of +3 and +1 don't make any sense
C) Ooh, we do have a +2 and -2 for the slopes, and... violà! plug in 1 for the x's and we get -1 for the y in both equations
D) slopes are closer than in A and B, but plugging in 1 doesn't get us -1

So the correct answer is:
C) y = 2x - 3 and y = −2x + 1