∟AEC = 2x + 40

∟CEB = x + 20

∟AEC + ∟CEB = 180° i.e. straight line AB

2x + 40 + x + 20 = 180°

3x + 60 = 180°

3x = 120°

x = 40°

AEC + CEB = AEB = 180 degrees ( Straight line angle)

Hence

2x + 40 + x + 20 = 180

3x + 60 = 180

3x = 120

x = 40 degrees .