Question

10x+7y=-10
-9x-7y=2

Answer 1

$10x+7y=-10$

$-9x-7y=2$

Adding two equations

$x=-8$

Substituting for x into the first equation of the system

$10(-8)+7y=-10$

$-80+7y=-10$

$7y=-10+80$

$y=\frac {70} 7$

$y=10$

Answer: x=-8 and y=10