Answer:
x = 9
Step-by-step explanation:
Angle PDC is an exterior angle. There is a theorem that says it is equal to the two angles (C and B) added together.
17x - 1 = 7x + 5 + 84
17x - 1 = 7x + 89
Subtract 7x
10x - 1 = 89
Add 1
10x = 90
Divide by 10
x = 9
