因式分解（有理数范围内）1.x⁴-12.x²+4x-xy-2y+43.4x²-12x+54.21x²-31x-225.4x²+4xy+y²-4x-2y-36.9x^5-35x³-4x7.3x²-6x8.49x²-259.6x²-13x+510.x²+2-3x11.12x²-23x-2412.(x+6)(x-6)-(x-6)13.8x²-1814.x²-(a-b)x-ab15.x²+x+y²-y-2xy16.若x-y=99,求x²+x+y²-y-2xy的值17.9x⁴+35x²-418.x²-y²-2yz-z²
问题描述：
因式分解（有理数范围内）
1.x⁴-1
2.x²+4x-xy-2y+4
3.4x²-12x+5
4.21x²-31x-22
5.4x²+4xy+y²-4x-2y-3
6.9x^5-35x³-4x
7.3x²-6x
8.49x²-25
9.6x²-13x+5
10.x²+2-3x
11.12x²-23x-24
12.(x+6)(x-6)-(x-6)
13.8x²-18
14.x²-(a-b)x-ab
15.x²+x+y²-y-2xy
16.若x-y=99,求x²+x+y²-y-2xy的值
17.9x⁴+35x²-4
18.x²-y²-2yz-z²
答