Answer: X=3 
Explanation:
You First Need To Understand That You Have 2 interior angles, and an exterior angle. 
The exterior angle theorem states that when a triangle's side is extended, the resultant exterior angle formed is equal to the sum of the measures of the two opposite interior angles of the triangle. 
This would mean interior angles, D and C add up to exterior angle, CBV.

Combine Like Terms, and Isolate X: 


Divide: 

3= x 
Checking: 
180 - <CBV = <CBD (this is a linear pair)
180- (20(3)+5) = <CBD
180-65= 115
115= 115
<D + <C + <CBD = 180
9x -2 +40 + 115= 180
9(3)-2 +40 +115 =180
25 + 40 + 115= 180
180 = 180