(2m+1/3n)^2 计算
问题描述：
(2m+1/3n)^2 计算
答
(2m+1/3n)^2
=4m^2+4/3mn+1/9n^2
(2m+1/3n)^2 计算
(2m+1/3n)^2
=4m^2+4/3mn+1/9n^2