Answer:
x = 71
Explanation:
BE = BC , therefore Δ BCE is isosceles with 2 base angle congruent
∠ BEC = ∠ BCE =
=
= 71°
∠ ABE and ∠ BEF are alternate angles and are congruent , so
∠ BEF = 142°
∠ BEC + ∠ FEC = ∠ BEF , that is
71° + x = 142 ( subtract 71° from both sides )
x = 71