7x - y = -10...........(1)
-7x + 5y = -6.........(2)
Add (1) and (2)
7x-y + (-7x) +5y = -10-6
=>
5y-y = -16
=>
4y=-16
=>
y=-16/4=-4
Substitute y in (1)
7x-(-4)=-10
7x=-10-4=-14
=>
x=-14/7=-2
Answer: the solution is x=-2, y=-4, or (-2,-4)
Check:
7(-2)-(-4)=-14+4=-10 ok
-7(-2)+5(-4)=14-20=-6 ok
