since M is the point of FG, then the halves FM and MG are twins.
[tex] \bf F\stackrel{\stackrel{FM = MG}{7x-15}}{\rule[0.35em]{10em}{0.25pt}}M\stackrel{\stackrel{MG}{7x-15}}{\rule[0.35em]{10em}{0.25pt}}G\\\\\\FG=FM+MG~~\begin{cases}FG=33\\FM=7x-15\\MG=7x-15\end{cases}\implies 33=(7x-15)+(7x-15)\\\\\\33=14x-30\implies 63=14x\implies \cfrac{63}{14}=x\implies \cfrac{9}{2}=x [/tex]
