Question

como resolve {2x-y=20
x+y=22

Answer 1

x+y= 22

2x-y= 20

*x=22-y

*2(22-y)-y=20

44-2y-y=20

-3y=-24

y=8

*x+8=22

x=14

Answer 2

Oi

2x - y = 20
 x + y = 22

soma as duas equaçoes

3x = 42 

x = 42 / 3

x = 14

acha y agora

14 + y = 22

y = 22 - 14

y = 8

S = {14, 8}