Answer:
a) 50
b) 6.71
c) 0.0681
Step-by-step explanation:
check the attached file below
The first one seems more reasonable
Answer:

Step-by-step explanation:
Angle EFB = 180 - 147 = 33 (Angles on a straight line add up to 180 degrees)
Angle FEB = 180 - 4x (Angles on a straight line add up to 180 degrees)
Since the angles in a triangle add up to 180 degrees ,

Remove brackets:

Add/Subtract:

Subtract 213 from both sides:


Divide both sides by -3:

