Please help me I don’t understand, find the missing side length

Given:
The length of the sides of the triangles is given.
Required:
Find the length of the missing side.
Explanation:
Let the length of the missing side is x.
By using the triangle proportionality theorem
[tex]\frac{5}{2}=\frac{x}{14-x}[/tex]solve the equation by cross multiplication.
[tex]\begin{gathered} 2x=5(14-x) \\ 2x=70-5x \\ 7x=70 \\ x=\frac{70}{7} \\ x=10 \end{gathered}[/tex]Final Answer:
The missing length will be