Respostas

2014-09-04T10:10:51-03:00
(x + 10) . (x - 10) (Aplico a propriedade distributiva).
x^2 - 10x + 10x - 100 ( - 10x corta com + 10x).
x^2 - 100
2014-09-04T10:12:17-03:00
(x + 10)(x-10)= x -10x +10x-100=x= -100