- #1
cmajor47
- 57
- 0
Homework Statement
Prove that for all integers n and m, if n-m is even then n3-m3 is even.
Homework Equations
Definition of even: n=2k
The Attempt at a Solution
Proof: Let n, m [tex]\in[/tex] Z such that n-m=2k
n-m=2k
n=2k+m
m=-2k+n
n3-m3=(2k+m)3-(-2k+n)3
I did all of this algebra out but I didn't think that it worked in showing that n3-m3 is even. Am I doing the proof wrong?