Respostas

2014-09-02T09:33:52-03:00
10y - 5 (1 + y) = 3 (2y -2) - 20
10y - 5 -5y = 6y - 6 - 20
5y = 6y - 26 + 5
5y - 6y = -21
-y = -21 (-)
y = 21
7 4 7
2014-09-02T09:34:47-03:00
10y-5-5y=6y-6-20
10y-5y-6y= -20 -6 +5
10y -11y = -26 +5
-1y= - 21 × (-1)
y = 21
5 4 5