Solve the following system of equations by substitution. PLEASE HELP!

Answer:
(1,-1)
Step-by-step explanation:
y = -1
5x+7y = -2
Substitute the first equation into the second
5x + 7(-1) =-2
5x -7 = -2
Add 7 to each side
5x-7+7 = -2+7
5x= 5
Divide by 5
5x/5 = 5/5
x =1
(1,-1)