因式分解练习题1112.7180.125-0.1254.71821.132.5+2.252.5+0.622.53a2(b-c)-(b-c)(a+b)4(2x+1)y2+(2x+1)2y5(x-y)n-(x-y)n-26m(a-m)(a-n)-n(m-a)(n-a)7x(m-n)2+(n-m)2y-z(n-m)3821a3b-35a2b393x2yz+15xz2-9xy2z103x3-6x2+3x11-3m2n2+6m2n-9m212x4-113(2x2-3x)-(6xy-9y)143(x-y)2-(y-x)315(x+y)2-916(x4+2x2+1)-a21725x2-(4a2-12ab+9b2)18(x2+y2)2-4x2y219、(x+y)2=5,(x-y)2=4,求x2+y2,xy20、x+y=5,xy=2,求x3y+2x2y2+xy321、若a2+b2+4a-6b+13=0,求a、b的值。