Question

10y-5 (1+y)=3 (2y-2)-20

Answer 1

10y- 5+5y=6y-6-20
10y-5y-6y=+5-6-20
5y-6y=-1-20
1y= -21
-21/1

espero ter ajudado 

Answer 2

10y-5(1+y)=3(2y-2)-20
10y-5-5y=6y-6-20
10y-5y-6y=-6-20+5
-y=-21 *(-1)
y = 21

tá valendo?
abraço