Question

escalona <br /> x+4y=-3<br /> x-y=2<br /> 3x+7y=-4

Answer 1

Olá,

x+4y = -3
x-y = 2 ⇒ L₂ - L₁
3x+7y = -4 ⇒ L₃ - 3L₁

x+4y = -3
x-y-(x+4y) = 2-(-3)
3x+7y-3(x+4y) = -4-3(-3)

x+4y = -3
x-x-y-4y = 2+3 ⇒ -5y = 5 ⇒ y = 5/-5 = -1
3x-3x+7y-12y = -4+9 ⇒ -5y = 5 ⇒ y = 5/-5 = -1

x+4y = -3
x = -3-4y
x = -3-4(-1)
x = -3+4
x = 1

Resposta:

x = 1 e y = -1