I'm working on an inverse function problem here and I'm not sure which is "more accurate" of an answer.

if $\displaystyle C=g(x)=900+50x$

find $\displaystyle g^-1(C)$

My answers are:

$\displaystyle

\frac{C-900}{50}

$ or $\displaystyle \frac{C}{50}-18$

edit - sorry for the mess, hit post instead of preview.