ANSWER
[tex]x = 11[/tex]
EXPLANATION
According to the exterior angle theorem, the sum of remote interior angles equal an exterior angle.
This implies that,
[tex](7x + 7) \degree + 66 \degree =(1 2x + 18) \degree[/tex]
We group the similar terms to get:
[tex]7 + 66 - 18 = 12x - 7x[/tex]
[tex]55= 5x[/tex]
Divide both sides by 5.
[tex]x = \frac{55}{5} [/tex]
[tex]x = 11[/tex]
