Question

Resolver os sistemas 3x-y=12
x+y=8

Answer 1

3x-y(x)=12
2x=12
x=12/2
x=6

x+y(x)=8
2x=8
x=8/2
x=4

Espero ter ajudado :)

Answer 2

3x-y=12
x+y=8----------------x=8-y

3(8-y)-y=12
24-3y-y=12
2y=-12
y=-6

x=8-y--------x=8-(-6)---------x=14