记算;(1/2m-1/3n)的平方-(1/2m+1/3n)的平方

问题描述:

记算;(1/2m-1/3n)的平方-(1/2m+1/3n)的平方

原式=[(1/2m-1/3n)+(1/2m+1/3n)][(1/2m-1/3n)-(1/2m+1/3n)]
=m*(-2/3n)
=-2/3mn