Question

Equaçoes do 1 grau com duas variaveis,sendo U = |R:
b){4x-y=8
{x+y=7

Answer 1

4x-y=8
x+y=7 -> x=7-y

4(7-y)-y=8
28-4y-y=8
-4y-y=8-28
-5y=-20
y=-20/-5
y=4

x+y=7
x+4=7
x=7-4
x=3