Question

因式分解：25(x+y)²-9(x-y)²；（x+y）²-4（x+y-1）.急求，谢谢~~

Answer 1

25(x+y)²-9(x-y)²
=[5(x+y)-3(x-y)][5(x+y)+3(x-y)]
=(2x+8y)(8x+2y)
=4(x+4y)(4x+y)

（x+y）²-4（x+y-1）.
=（x+y）²-4（x+y)+4
=(x+y-2)^2

追问

还有几题：a²-x²-2x-2a；1-m²-n²+2mn；x的4次方-5x²+4 不好意思啊，麻烦你了。。。

追答

a²-x²-2x-2a
=(a-x)(a+x)-2(x+a)
=(a-x-2)(a+x)

1-m²-n²+2mn
=1-(m-n)^2
=(1-m+n)(1+m-n)

x^4-5x^2+4
=(x^2-1)(x^2-4)
=(x-1)(x+1)(x-2)(x+2)

先采纳后求助哦