# if $b^k$ is a primitive root, then $b$ is a primitive root

Any hints or strategies would be greatly appreciated:

If $m$ is an integer and $b^k$ is a primitive root mod $m$, then $b$ is a primitive root mod $m$.

I am reviewing material from my elementary number theory course. I had a true/false question that I think is true (by process of elimination of how many "trues" the problem set was supposed to have). But I and am absolutely stuck on trying to prove it.