Since G is the midpoint of FH,
[tex]\begin{gathered} FG=GH \\ \Rightarrow11x-7=3x+9 \\ \Rightarrow11x-3x=9+7=16 \\ \Rightarrow8x=16 \\ \Rightarrow x=2 \end{gathered}[/tex]
Therefore,
[tex]\begin{gathered} FG=11x-7=11\cdot2-7=22-7=15 \\ \Rightarrow FG=15 \end{gathered}[/tex]
The answer is 15, option a.
