Question

1) acolada x+y=8
2x+y=11

2) acolada x-2y=10
2x-y=14

Answer 1

x+y=8
2x+y=11

y=8-x
2x+8-x=11
x=3
y=8-3=5

x-2y=10
2x-y=14

x=10+2y
2(10+2y)-y=14
20+4y-y=14
3y=-6
y=-2
x=10+2*(-2)=10-4=6