x2-3xy-10y2-x+8y-2 =(x-5y)(x+2y)-x+8y-2=(x-5y+1)(x+2y-2)
分解后应该是(x-5y+1)(x+2y-2)过程如下：x2-3xy-10y2-x+8y-2 =(x-5y)(x+2y) -x+8y -2=(x-5y+1)(x+2y-2)
