First start of by collecting like terms: 9x+x+x and -8+10+2. There the x's equal 11x and the numbers equal 4. We add those together to make 11x+4. As this is a triangle all the angles add up to 180 degrees, so we equal 11x+4 to 180 degrees. Like 11x+4=180. Subtract the 4 from each sides, to get 11x=176. Then divide both sides by 11, to get x=16
