$$ \begin{aligned} y &= \frac{ \log_\mathrm{e} \left( \frac{x}{m} - sa \right) }{r^2 } \\ yr^2 &= \log_\mathrm{e} \left( \frac{x}{m} - sa \right) \\ \mathrm{e}^{yr^2} &= \frac{x}{m} - sa \\ m\mathrm{e}^{yr^2} &= x - msa \\ m\mathrm{e}^{rry} &= x - mas \end{aligned} $$