Respostas

2014-02-11T15:21:43-02:00
A)
10y-5(1+y) = 3(2y-2)-21
10y-5+5y = 6y-12-21
15y-5 = 6y-12-21
15y-6y = -33+5
9y = -28
y = 28/9 
y = 3,111

B)
2(x+4)+3(x+2) = 2x+12
2x+8+3x+6 = 2x+12
5x-2x = -14+12
3x = -2
x = -2/3