Q1)
From circle properties - triangle in a semicircle is a right triangle. Right?
Hence, ACD and AFE are right triangles.
AOF is also a right isoc. triangle.

From this, angle FAO = 45

From the question,
BD = 1/2 AD implies based on trigo or basic triangle properties that triangle ACD is half an equilateral triangle.

This yields angle CAD = 30

x = angle CAF = Angle FAO - Angle CAD = 45 - 30 = 15

Q2)