Start with

Multiply both sides by 3:

Expand both sides:

Subtract
from both sides:

Subtract 20 from both sides:

Divide both sides by 2:

They are similar, but I don't exactly know why. It has something to do with the angles, I know that.
The answer to this question is B
Answer:
x = 98
Step-by-step explanation:
The measure of the exterior angle of a triangle is equal to the sum of the opposite interior angles
x = 53+ 45
x = 98