NOTE: Angles not necessarily drawn to scale.

Answer:
x = 45°
Step-by-step explanation:
Vertical Angle Theorem
When two straight lines intersect, they form two pairs of angles. The vertically opposite (non-adjacent) angles are congruent (equal).
From inspection of the given diagram, the straight line with points C and D and the straight line with points F and G intersect at point E.
Therefore, angles ∠FEC and ∠DEG are vertically opposite, and so they are equal.
From inspection of the diagram:
Therefore:
⇒ ∠FEC =∠DEG
⇒ x = 45°