问题补充:
把x2-1+2xy+y2的分解因式的结果是A.(x+1)(x-1)+y(2x+y)B.(x+y+1)(x-y-1)C.(x-y+1)(x-y-1)D.(x+y+1)(x+y-1)
答案:
D
解析分析:观察发现:一、三、四项一组,符合完全平方公式,然后运用平方差公式继续分解.
解答:x2-1+2xy+y2,=(x2+2xy+y2)-1,=(x+y)2-1,=(x+y+1)(x+y-1).故选D.
点评:本题考查了分组分解法分解因式,观察各项之间的联系,能够合理分组是解题的关键.
把x2-1+2xy+y2的分解因式的结果是A.(x+1)(x-1)+y(2x+y)B.(x+y+1)(x-y-1)C.(x-y+1)(x-y-1)D.(x+y+1)(