Question

Resolva cada equação para x = y - 3 e encontre o valor de y

a) x + 2y = 7

b) 2x - y = -8

Answer 1

A) y-3+2y=7

3y=10

y=10/3

B) 2y-6-y=8

y=14

Answer 2

a) x+2y=7
(y-3)+2y=7
-3y+2y=7
-y=7 . (-1)
y= -7

b) 2x-y= -8
2(y-3)-y= -8
2y-6-y= -8
2y-y= -8+6
y= -2