Question

因式分解：1、-4ab-4a²-b² 2、3ab²+6a²b+3a³ 3、49(2a-3b)²-9(a-b)²

答就加分10分

Answer 1

-4ab-4a²-b² =-（2a+b）²
3ab²+6a²b+3a³ =3a(b²+2ab+a²)=3a(a+b)²
49(2a-3b)²-9(a-b)²=(14a-21b)²-(3a-3b)²=(17a-24b)(11a-18b)

Answer 2

-4ab-4a²-b² =-(2a+b)²
3ab²+6a²b+3a³
=3a(a+b)²
49(2a-3b)²-9(a-b)²
=[7(2a-3b)+3(a-b)][7(2a-3b)-3(a-b)]
=(17a-24b)(11a-18b)