Question

resolve equacao do 1grau -2x+y=7 e x+y=0

Answer 1

Olá,

-2x+y = 7 ⇒ y = 7+2x
x+y = 0

x+(7+2x) = 0
x+2x+7 = 0
3x+7 = 0
3x = -7
x = -7/3

y = 7+2x
y = 7+2(-7/3)
y = 7-14/3
y = (21-14)/3
y = 7/3

Resposta:

(x,y) = (-7/3,7/3)