Answer:
34°
Step-by-step explanation:
∠EFG = ∠EFH + ∠HFG
= 90° + 42°
= 132°
Exterior angle property:
Exterior angle equals the sum of two interior opposite angles (remote angles).
∠EFG is the exterior angle and ∠D and ∠E are the opposite interior angles.
∠D + ∠F = ∠EFG
2x + 64 = 132
Subtract 64 from both sides,
2x = 132 - 64
2x = 68
Divide both sides by 2,
x = 68 ÷ 2
[tex]\sf \boxed{\bf x = 34^\circ}[/tex]