因式分解：(1)3分之1x²y-3y (2)-4（x-2y）²+9（x+y）²

来源：学生作业学帮网编辑：学帮网时间：2024/06/08 19:11:26

：(1)3分之1x²y-3y
=y/3(x²-9)
=y/3(x+3)(x-3)
(2)-4（x-2y）²+9（x+y）²
=9(x+y)²-4(x-2y)²
=(3x+3y+2x-4y)(3x+3y-2x+4y)
=(5x-y)(x+7y)