Answer:
C) 100
Step-by-step explanation:
line AC intersects line DB,
hence ∠AEB and ∠DEC are opposite angles and thus
∠AEB = ∠DEC
5x-10 = 4x+12 (subtract 4x from both sides)
5x - 4x - 10 = 12
x - 10 = 12 (add 10 to both sides)
x = 12 + 10 = 22 degrees
∠DEC = 4x+12
= 4(22) + 12
= 88 + 12
= 100 degrees
