Angle AED is supplementary to angle AEB.
Angles AEB and DEC are vertical angles, so their measures are equal.
5x = 3x + 10
2x = 10
x = 5
m<AEB = 5x = 5 * 5 = 25
Angle AED is supplementary to <AEB, so
m<AED + m<AEB = 180
m<AED + 25 = 180
m<AED = 155
Answer is D.
