问题
解答题
分解因式:
(1)18(m+n)2-8(m-n)2
(2)x2-y2-z2+2yz.
答案
(1)18(m+n)2-8(m-n)2=2[(3m+3n)2-(2m-2n)2]=2(3m+3n+2m-2n)(3m+3n-2m+2n)=2(5m+n)(m+5n);
(2)x2-y2-z2+2yz=x2-(y-z)2=(x+y-z)(x-y+z).
分解因式:
(1)18(m+n)2-8(m-n)2
(2)x2-y2-z2+2yz.
(1)18(m+n)2-8(m-n)2=2[(3m+3n)2-(2m-2n)2]=2(3m+3n+2m-2n)(3m+3n-2m+2n)=2(5m+n)(m+5n);
(2)x2-y2-z2+2yz=x2-(y-z)2=(x+y-z)(x-y+z).