分解因式1.12a³b²-9a²b+3ab1.12a³b²-9a²b+3ab 2.a³-4a²b+4ab² 3.(3x+y)²-(x-3y)² 4.(2a-b)²+8ab 分解因式

12a³b²-9a²b+3ab
=3ab(4a^2b-3a+1)
a³-4a²b+4ab²
=a(a^2-4ab+4b^2)
=a(a-2b)^2
.(2a-b)²+8ab
=4a^2-4ab+b^2+8ab
=4a^2+4ab+b^2
=(2a+b)^2

1、12a³b²-9a²b+3ab =3ab(4a²b-3a+1)
2、a³-4a²b+4ab² =a(a² -4ab+4b²)=a(a-2b)²
3、(3x+y)²-(x-3y)²=（3x+y+x-3y)(3x+y-x+3y)=(4x-2y)(2x+4y)=4(2x-y)(x+2y)
4、(2a-b)²+8ab =4a ² -4ab+b²+8ab=4a²+4ab+b²=(2a+b)²