Answer:
x = 11
Step-by-step explanation:
The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
∠ FEB and ∠ DEB are adjacent angles and supplementary, thus
∠ FEB = 180 - 4x , so
180 - 4x + x = 147, that is
180 - 3x = 147 ( subtract 180 from both sides )
- 3x = - 33 ( divide both sides by - 3 )
x = 11
