What you're looking for is to simplyfy the like terms and then isolate the variable. So basically, write everything down and solve it like normal. We know that straight lines are worth 180° and right angles are 90° so that's what's gonna be on one side of the equal sign, and all the other numbers on the other side. Like this:
8.
180 = x + 1 + 3x + 9
180 = 4x + 10
170 = 4x
42.5 = x
If it's hard to see what I'm doing, just write the first part out and solve like regular algebra then check if you got the same answer.
Good luck :)