(1)我发现的规律：第n个算式为
(n+1)²-n²=2n+1
(2)以下两题证明如下：
(n+1)²-n²
=n²+2n+1-n²
=2n+1
(3) (n+1)²-n²
=[(n+1)+n][(n+1)-n]
=(2n+1)×1
=2n+1

望采纳,谢谢!第二个是用多项式乘法啊。