因式分解: (1)x2-3xy-10y2+x+9y-2; (2)x3-11x2+31x-21.

问题描述:

因式分解:
(1)x2-3xy-10y2+x+9y-2;
(2)x3-11x2+31x-21.

(1)原式=(x+2y)(x-5y)+2x+4y-x+5y-2 =(x+2y)(x-5y)+2(x+2y)-(x-5y+2)=(x+2y)(x-5y+2)-(x-5y+2)=(x+2y-1)(x-5y+2);(2)原式=(x3-1)-(11x3-31x+20)=(x-1)(x2+x+1)-(11x-20)(x-1...