Question

1) Resolva as equações abaixo:
a)
$(x + y = 5 \\ (2x - y = 9$




b)
$(3x - y = 10 \\ (x + y = 18$
​

Answer 1

Resposta:

A) x=14/3 ; y=1/3

B) x=7; y=11

Explicação:

A)

I:x+y=5

II:2x-y=9

I:x+y=5 => x=5-y

II:2x-y=9 => 2(5-y)-y=9 =>10-2y-y=9 => -3y=9-10 => -3y=-1 => (-3y=-1)(-1) => 3y=1 => y=1/3

I:x=5-y => x=5-1/3 => x=15-1/3 => x=14/3

B)

I:3x-y=10

II:x+y=18

II:x+y=18 => x=18-y

I:3x-y=10 => 3(18-y) -y=10 => 54-3y-y=10 => -4y=10-54 => -4y=-44 => y=-44/-4 => y=11

II: x=18-11 => x=7