Question

观察等式：（1）9-1=2×4，（2）25-1=4×6，（3）49-1=6×8，......按照这种规律写出第n（n为正整数）个等

写出第n个等式

Answer 1

n^2-1=(n-1)*(n+1)

Answer 2

(2n+1)^2=(2n)*(2n+2)

Answer 3

3+2*(n-1)-1=(n*2)*(n*2+2)

Answer 4

(2n+1)^2=2n*（2n+2)

Answer 5

n *n-1=(n-1)*(n+1)