Respostas

2013-07-11T17:01:54-03:00
 (5a + 7ab - 4b) + (-2a + 3ab + 3b) =
5a + 7ab - 4b - 2a + 3ab + 3b
5a - 2a - 4b + 3b + 7ab + 3ab
3a - b + 10ab   
 acho que e assim
1 3 1
2013-07-11T17:06:09-03:00
(5a+7ab-4b)+(-2a+3ab+3b)=
3a+10ab-b=
a(3+10b) -b .