Question

5) resolva os sistemas abaixo:

A) {3x+2y=-5
x- 2y=-7


b) { 4x - y=2
3x + 2y=7


está tudo na mesma chave, me ajuda pfvr​

Answer 1

Resposta:

a) $x=-3$ | $y= 2$

b) $x=1$ | $y=2$

Explicação passo-a-passo:

a)

$\left \{ {{3x+2y=-5} \atop {x-2y=-7}} \right. \\\\x=-7+2y\\x=2y-7$

$3(2y-7)+2y=-5\\6y-21+2y=-5\\8y=-5+21\\8y=16\\y=2$

$x=2y-7\\x=2(2)-7\\x=4-7\\x=-3$

b)

$\left \{ {{4x-y=2} \atop {3x+2y=7}} \right.\\\\4x-2=y\\y=4x-2$

$3x+2y=7\\3x+2(4x-2)=7\\3x+8x-4=7\\11x=7+4\\11x=11\\x=1$

$4x-y=2\\4(1)-y=2\\4-y=2\\4-2=y\\y=2$