Question

Resolver os sistemas
×+y=19
2×+y=31

Answer 1

x + y = 19
2x + y = 31

x + y = 19 (-1)
-x - y = -19

-x - y = -19
2x + y = 31
x = 12

x + y = 19
12 + y = 19
y = 19 - 12
y = 7

Resposta: x = 12; y = 7