Answer :

So,

As you can notice, the measure of the angle TKF is 90°.

So, we could write:

[tex]\begin{gathered} 5(x+7)=90 \\ 5x+35=90 \\ 5x=90-35 \\ 5x=55 \\ x=11 \end{gathered}[/tex]

Therefore, x=11.