Question

n and a are integers.
Explain why (n^2 - a^2) - (n - a)^2 is always an even integer.

Answer 1

u can write (n^2 - a^2) as (n-a)(n+a)
(n-a)(n+a)-(n - a)^2
(n-a)[n+a-n+a]
(n-a)2a
2[a(n-a)] = multiple of 2 always soeven

Answer 2

used formula a2-b2=(a-b)(a+b)