Hey there,
Angle AEB + Angle CED = 180 degrees (vertically opposite angles)
(5x-10) degrees + (3x + 40) degrees = 180 degrees
5x -10 + 3x + 40 = 180 degrees
5x + 3x= 180 + 10 - 40
8x = 150
x = 150 / 8
= 18.75 degrees
Angle AEB = (18.75 x 5) - 10
=83.75 degrees.
Hope this helps ^_^
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