1：
=（a-b)(x-y-x-y)
=(a-b)(-2y)
2:
=4a^2+4ab+b^2+8ab
=4a^2+12ab+b^2
3:
=[(4x)^4+1][(2x)^2+1]][(2x)^2-1]
4:
=(x-9)(x+4)
5:
=(x-12)(x-3)
没法写过程,
到底是不是分解因式