Respostas

2013-11-28T16:19:05-02:00
(a-7)²
a²-2.a.-7+(-7)²
a²+14a+49
1 5 1
2013-11-28T16:23:12-02:00
( a - 7 ) . ( a - 7 ) = 
a² - 7 a - 7 a + 49 = 
a ² - 14 a + 49