问题标题：
分解因式的几个题,xy(x-y)-x(x-y)^2-a^2+1.96b^2
问题描述：
分解因式的几个题,
xy(x-y)-x(x-y)^2
-a^2+1.96b^2
胡文军回答：
xy(x-y)-x(x-y)(x-y)
=(x-y)[xy-x(x-y)]
=(x-y)(xy-x^2+xy)
=(x-y)(2xy-x^2)
=x(x-y)(2y-x)
-a^2+1.96b^2
=1.96b^2-a^2
=(1.4b+a)(1.4b-a)
