Question

Prove that if n^2 - (n - 2)^2 is not divisible by 8 then n is even

Answer 1

n^2 - (n - 2)^2=n^2-(n^2-2n+4)=n^2-n^2+2n-4=2n-4
then we have
2n-4
when n is even
2(2m)-4=4(m-1) hmm not convinced of the question , when m is odd then n^2 - (n - 2)^2 divisible by 8 then

Answer 2

@ganeshie8

Answer 3

n^2 - (n - 2)^2=n^2-(n^2-4n+4)=n^2-n^2+4n-4=4n-4 = 4(n-1)

@Marki

Answer 4

oh yes !

Answer 5

Thanks very much both :)