分解因式 1. (a+b)^2-8(a+b)+16 解,得：==[(a+b)-4]^2==(a+b-4)^2 2. 9(a-b)^2-4(a+b)^2 解,得：==[3(a-b)-2(a+b)][3(a-b)+2(a+b)]==(3a-3b-2a-2b)(3a-3b+2a+2b)==(a-5b)(5a-b)3. (x-2y)^2-6(2y-x)(x+y)+9(x+y)^2...第三题是错的！答案是（4x+y）^23. (x-2y)^2-6(2y-x)(x+y)+9(x+y)^2解，得：== (x-2y)^2+6(x-2y)(x+y)+9(x+y)^2==[ (x-2y)+3(x+y)]^2==(x-2y+3x+3y)^2==(4x+y)^2