I'm not sure how i'm supposed to use this equation. can someone me and explain?

So QRS equals to 158 degrees. Therefore, you need to do 8x+8+2x=158. This is so then you can find x. In order to find x, you'll need to combine the 2x and 8x(10x+2=158). Then subtract 2 from both sides(10x=156). Finally divide by 10(x=15.6). In order to find TRS, multiply 15.6 by 2 to get the angle measure. If you want to find QRT, plug 15.6 into the equation(multiply 8 and 15.6 and add 8=132.8)

That they are numbers and related to each other.