Question

How can x+8=-x+7 be set up as a system of equations
A. Y=x+8
Y=-x+7
B. y=x+8
Y=-3x+7
C. Y=x+5
Y=-2x+11
D. Y=8
Y=-3x+7

Answer 1

This equation looks like what you get after substituting for y for the system of equations:

y = x + 8
y = -x + 7

Answer 2

If x + 8 = y and y = -x + 7, then by substitution, x + 8 = -x + 7