Solve the following system of equation: 7x+5y=-25, 3x+7y=-1

m3:   7x+5y=-25
m7:   3x+7y=-1 

21x+15y=-75
21x+49y=-7 


21x+49y=-7
-21x-15y=75 

34y=68 
y=2 

3x+7(2)=-1 
3x=-15 
x=-5