Question

Prrove that n2 -1 is divisible by 8 for every odd integer n

Answer 1

n must be odd integer
let n =4q+1
(4q+1)2-1
4q2+(1)2+2×4q
16q2+1+8q-1
16q2+8q
8(2q2+q)

8m where m=2q2+q