Thread: Equivalence Relations

I am having trouble starting off with the two following problems.

• Let a R b on Q^+ if and only if a = b^k for some k is an element of Q

• Let a ~b on Z if and only if 7 divides (a-b)

Can somebody show me how to prove the reflexive property for each. I can prove symmetric and transitive if I see how to approach each problem. Thanks

Both are so simple.

thanks