分解因式:9(m+2n)^2-4(2m-n)^2
问题描述:
分解因式:9(m+2n)^2-4(2m-n)^2
答
原式=[3(m+2n)]²-[2(2m-n)]²
=(3m+6n)²-(4m-2n)²
=(3m+6n+4m-2n)(3m+6n-4m+2n)
=(7m+4n)(8n-m)