(look at image) can i get help with #21?

Step-by-step explanation:
or, 6x=4x+16
or, 6x-4x=16
or, 2x=16
or, x=8
replacing value of x
m<AED=6×
=6*8
=48
m<BEC=m<AED=48(V.O.A)
m<AED+m<DEC= 180(straight line)
or, 48+11Y=180
or, 11y=180-48
or, 11y= 132
or, y=132/11
or, y= 12
replacing value of y
m<DEC=11y
=11*12
=132
m<AEB=m<DEC=132(V.O.A)