Question

x^2-xy-2y^2-2x+7y-3如何因式分解？

Answer 1

      解：x2-xy-2y2-2x+7y-3=(x+y)(x-2y)+(x+y)-3(x-2y)-3=[(x+y)(x-2y)-3(x-2y)]+[(x+y)-3]=(x-2y)(x+y-3)+(x+y-3)=(x+y-3)(x-2y+1)