1.(3m+2n)^2-4(m-n)^2 2.3a(a+b)^2-27ab^2
问题描述：
1.(3m+2n)^2-4(m-n)^2 2.3a(a+b)^2-27ab^2
答
1.(3m+2n)^2-4(m-n)^2=(3m+2n+2m-2n)(3m+2n-2m+2n)=5m(m+4n)
2.3a(a+b)^2-27ab^2=3a[(a+b)^2-9b^2]=3a(a+b+3b)(a+b-3b)=3a(a+4b)(a-2b)