Question

resolvendo o sistema de equações abaixo, obteremos

x + 2y = 7
3x -y = 7

a) x= 1 e y= -4
b) x= -1 e y= -3
c) x= -1 e y= -4
d) x= 3 e y= 2

Answer 1

Resposta:

S = {3, 2}

Explicação passo-a-passo:

Vamos lá!

$\left \{ {{x + 2y = 7} \atop {3x -y = 7}} \right. ||x=7-2y\\\\\\3(7-2y)-y=7\\\\21-6y-y=7\\\\-7y=7-21\\\\y=-14:(-7)\\\\y=2\\\\\\x=7-2.2\\\\x=7-4\\\\x=3\\\\\\Prof Alexandre$