[tex]\bf \begin{cases} UW = m\\ WX = y+14 \end{cases} ~\hfill WX = y+14\implies \boxed{W=\cfrac{y+14}{X}} \\\\\\ \stackrel{\textit{doing substitution on the 1st equation}}{UW = m\implies U=\cfrac{m}{W}\implies }U=\cfrac{m}{\frac{y+14}{X}}\implies U=\cfrac{\frac{m}{1}}{\frac{y+14}{X}} \\\\\\ U=\cfrac{m}{1}\cdot \cfrac{X}{y+14}\implies U=\cfrac{mX}{y+14}\implies \stackrel{\textit{multiplying both sides by X}}{UX=\cfrac{mX^2}{y+14}}[/tex]
