x2-xy-2y2-x-7y-6=(x-2y+A)(x+y+B).求A、B的值.
问题描述:
x2-xy-2y2-x-7y-6=(x-2y+A)(x+y+B).求A、B的值.
答
(x-2y+A)(x+y+B)=x2+xy+Bx-2xy-2y2-2By+Ax+Ay+AB=x2-xy-2y2+(B+A)x+(-2B+A)y+AB.∵x2-xy-2y2-x-7y-6=(x-2y+A)(x+y+B),∴B+A=−1−2B+A=−7AB=−6,解得A=−3B=2.故A的值为-3,B的值为2....