Hey there! I'm happy to help!
These are corresponding angles since they both connect a parallel line and the transversal. This means they are congruent and have the same value. So, we can set up the following equation.
8x-8=5x+25
Subtract 5x from both sides.
3x-8=25
Add 8 to both sides.
3x=33
Divide both sides by 3.
x=11.
Have a wonderful day! :D