Answer:

Step-by-step explanation:
From the diagram which I have drawn and attached below:

Next, in the triangle, the sum of the three interior angles:

The value of angle x is 35 degrees.
The answer is 8x-1 I believe
The process used is division. If you go to math is fun.com they have a really good step by step example on how to do this. Please give this brainliest answer if I helped.