Find $r$ given that: $M=aY + B(r-x)^{-c}$ I have an equation like so:

$M=aY + B(r-x)^{-c}$

Assuming all the variables are positive, how do I find $r$? I've worked it out to about this point:
$M(r-x)^c=aY(r-x)^c+B$
$r-x=\sqrt[c]{\frac{aY(r-x)^c+B}{M}}$
$r=\sqrt[c]{\frac{aY(r-x)^c+B}{M}}+x$
But I don't think this is right considering there's still $(r-x)^c$ on the right hand side?

$$M=aY + B(r-x)^{-c}\\\frac {M-aY}B=(r-x)^{-c}\\\frac B{M-aY}=(r-x)^c\\
\sqrt[c]{\frac B{M-aY}}=r-x\\x+\sqrt[c]{\frac B{M-aY}}=r$$
