Okay so these are vertical angles, which means that they are going to be equal to each other, aka CONGRUENT.
This means that your equation is going to be:
2x + 15 = 145
Now let us solve that equation.
You are going to subtract 15 from each side, so subtract 15 from 15, and subtract 15 from 145, meaning that your new equation is going to be:
2x = 130
Now your are going to divide each side my 2. This means you are going to divide 2x by 2 and divide 130 by 2. This means:
x= 65.
I hoped that I helped ;)