题目内容
运用公式法分解因式:
x3y2-4x
x3y2-4x=x(x2y2-4)=x(xy+2)(xy-2)
(1)a2+4ab+4b2 (2)2xy-x2-y2
(3)-9x2-y2+6xy (4)81a4-18a2+1
(1);
(2);
(3);
(4).