Question

y = x -2
2x-y = 7
qual o x ?

Answer 1

y = x -2
2x -y = 7

Substituir valor de y

2x - y = 7
2x - ( x - 2 ) = 7 
2x -x + 2 = 7
x = 7 - 2 
x = 5

Resposta x = 5