There are 180 degrees in a triangle, so what you want to do from there is make an equation 35 + 65 + 2x = 180 from there add like terms 100 + 2x = 180 then subtract 100 from 180 to get 2x alone 100 - 100 + 2x = 180 - 100
2x = 180 from there divide 2 from 180 and get the answer x = 78 degrees
