We will follow this strategy: we will find the value of x using a theorem about the sum of interior angles of any polygon, and then we will compute 2x to find A.
The theorem states that the sum of the interior angles of any polygon with 
 sides is 

Your polygon has seven sides (so 
), and the sum of the interior angles is

So, using the theorem, we know that
.
Since 
 and 
, we have 
