3) Angle plus the angle will be the sum of the line making it 180 degrees.
4) X being the missing variable number to solve the final product of 180 with both angles missing a variable number. With angle 1 being 11x-6 and angle 2 being 4x+21
5) This is the after work when 11x and 4x was combined giving 15x and 21 and -6 combined giving 15 which combines both angles helping to find the sum in which will be 180
6) The after work, after 180 was subtracted with 15 giving it 165
7) The after work, after 165 was divided by 15 giving it 11, with 11 being the missing value of x