Question

因式分解题目(写出过程)

1. a²-b²-2b-1 2.（xy+1）²-（x+y）² 3.x²-2x-4y²-4y
4.（x²+2x）²-2（x²+2x）-3
两楼的答案没完整= =

Answer 1

1,a2-b2-2b-1 =a2-(b2+2b+1)
=a2-(b+1)2
=(a+b+1)(a-b-1)

2,（xy+1）2-（x+y）2=(xy+1+x+y)(xy+1-x-y)
=[(xy+x)+(y+1)][(xy-x)-(y-1)]
=[x(y+1)+y+1)][x(y-1)-(y-1)]
=(x+1)(y+1)(x-1)(y-1)

3,x2-2x-4y2-4y= x2-4y2-2x-4y
=(x+2y)(x-2y)-2(x+2y)
=(x-2y-2)(x+2y)

4,（x2+2x）2-2（x2+2x）-3=(x2+2x+1)(x2+2x-3)
=(x+1)2(x-1)(x+3)

楼主，以上过程相当详细，不信你看不懂。。。
记得给分哦~

Answer 2

1. a²-b²-2b-1
=a^2-(b^2+2b+1)
=a^2-(b+1)^2
=(a+b+1)(a-b-1)

2.（xy+1）²-（x+y）²
=(xy+1+x+y)(xy+1-x-y)
=(x+1)(y+1)(x-1)(y-1)

3.x²-2x-4y²-4y
=x^2-4y^2-2x-4y
=(x+2y)(x-2y)-2(x+2y)
=(x+2y)(x-2y-2)

4.（x²+2x）²-2（x²+2x）-3
=(x^2+2x-3)(x^2+2x+1)
=(x+3)(x-1)(x+1)^2

Answer 3

1. a²-b²-2b-1
=a^2-(b+1)^2
=(a+b+1)(a-b-1)

2.（xy+1）²-（x+y）²
=(xy+1+x+y)(xy+1-x-y)

3.x²-2x-4y²-4y
=(x+2y)(x-2y)-2(x+2y)
=(x+2y)(x-2y-2)

4.（x²+2x）²-2（x²+2x）-3
=(x^2+2x+1)(x^2+2x-3)