Well I have to prove the following statements are equivalent: a. y is a rational number b. y/3 is a rational number c. 2y+5 is a rational number So a -> b -> c -> a I'm not quite sure how you are suppose to prove something is rational however. I started like this: * y = q/r Where q & r are integers, r is not 0, no common factors other than 1 [Therefore rational] * y/3 q/r/3 ... (q/r)(1/3)= q/3r ... Which is rational because everything is integer math? * 2y+5 ... 2(q/r) + (5/1) ... same reason This doesn't seem to work like the ones I've done before with proving something is even (2n) or odd (2n+1). Is there some step I'm not getting?