Question

What's the solution of the system?
7x+5y=19
-7x-2y=-16

Answer 1

add them equations, y's cancel

7x+5y=19
-7x-2y=-16 +
0x+3y=3

3y=3
divide by 3
y=1

sub back
7x+5y=19
7x+5(1)=19
7x+5=19
minus 5 both sides
7x=14
divide by 7
x=2

(x,y)
(2,1)

solution is (2,1)