(2m+n-1)^2化简
问题描述：
(2m+n-1)^2化简
(2m+n-1)^2化简
答
(2m+n-1)²
=(2m)²+n²+(-1)²+2×2mn+2×2m(-1)+2n(-1)
=4m²+n²+1+4mn-4m-2n
提示运用公式(a+b+c)^2=a^2+b^2+c^2+2ab+2ac+2bc