把代数式ab2﹣6ab+9a分解因式,下列结果中正确的是( )
A. a(b+3)2 B.a(b+3)(b﹣3) C.a(b﹣4)2 D. a(b﹣3)2
D 解:ab2﹣6ab+9a,
=a(b2﹣6b+9),
=a(b﹣3)2.