分解因式.1）.9(a-b)^2-25(a+b)^22).(x+y)^3-4xy(x+y)3).(x-2)^2+10(x-2)+254).8a-4a^2-4

Question

分解因式.
1）.9(a-b)^2-25(a+b)^2 2).(x+y)^3-4xy(x+y) 3).(x-2)^2+10(x-2)+25
4).8a-4a^2-4

Answer 1

1）.9(a-b)^2-25(a+b)^2
=[3(a-b)]²-【5(a+b)]²
=(3a-3b+5a+5b)(3a-3b-5a-5b)
=(8a+2b)(-2a-8b)
=-4(4a+b)(a+4b)
2).(x+y)^3-4xy(x+y)
=(x+y)[(x+y)²-4xy]
=(x+y)(x-y)²
3).(x-2)^2+10(x-2)+25
=(x-2+5)²
=(x+3)²