计算:(x-y)(1/9x-y)-(1/3x-y)(1/3x+y)
问题描述:
计算:(x-y)(1/9x-y)-(1/3x-y)(1/3x+y)
答
:(x-y)(1/9x-y)-(1/3x-y)(1/3x+y)
=x^2/9-10xy/9+y^2-x^2/9+y^2
=2y^2-10xy/9