Answer:
x = 33
Explanation:
a quadrilateral inscribed in a circle is a cyclic quadrilateral
the opposite angle of a cyclic quadrilateral sum to 180°
∠ def and ∠dcf are opposite angles , then
3x + 7 + 2x + 8 = 180
5x + 15 = 180 ( subtract 15 from both sides )
5x = 165 ( divide both sides by 5 )
x = 33