Answer:
12y = -7
Step-by-step explanation:
Since I find it difficult to properly align parts of the equation for a vertical presentation, I like to show the difference as the difference of the left side being equal to the difference of the right side:
(2x +7y) -(2x -5y) = (-8) -(-1)
x(2 -2) +y(7 -(-5)) = -8 +1
12y = -7 . . . . the difference of the equations
