Question

初高中衔接的一些数学题.因式分解方面的..

1.x2-2xy-3y2+x+5y-2

2.x2-x-1

3.3x2-7xy-6y2+7x+12y-6

4.x2+2xy+y2-2x-2y-3

5.a2+b2-c2-4d2-2ab+4cd

Answer 1

1.x2-2xy-3y2+x+5y-2
=(x+y-1)(x-3y+2) 双十字法
2.x2-x-1
△=1+4=5
x2-x-1 =(x-(1+√5)/2)(x-(1-√5)/2)
3.3x2-7xy-6y2+7x+12y-6
=(3x+2y-2)(x-3y+3)
4.x2+2xy+y2-2x-2y-3
=(x+y-3)(x+y+1)
5.a2+b2-c2-4d2-2ab+4cd
=(a-b)^2-(c-2d)^2
=(a-b+c-2d)(a-b-c+2d)