Algebra math help? One question...

What is the value of the y variable in the solution to the following system of equations?
5x + 4y = 1
4x + 3y = -1

A. -7
B. 7
C. 9
D. -9

I've been stuck on this for like, 30 minutes... This is my last question on my worksheet and I really need help! If you could, would you show how you got the answer? Thanks, so much!

multiply eqn 1 by 4 =>20x+16y=4
multiply eqn 2 by 5 =>20x+15y=-5
subtract these y=9

why are you doing math its the middle of the summer.