SOLUTION
Triangle FGH is similar to triangle ABC
Therefore the ratio of their corresponding sides will be equal.
That is
[tex]\begin{gathered} \frac{FG}{BA}=\frac{GH}{BC}\text{ = }\frac{FH}{CA} \\ \\ So\text{ let's take just these sides ratios } \\ \frac{GH}{BC}\text{ = }\frac{FH}{CA} \\ \\ \frac{7}{14}=\frac{6}{x} \\ \text{cross multiply } \\ 7x\text{ = 6x14} \\ x\text{ }=\text{ }\frac{84}{7} \\ x\text{ = 12} \end{gathered}[/tex]Therefore, x = 12