angle 1 and 2 are going to add up to 180 since it is a straight line so 100 + x = 180 X= 80 so angle 2 is 80 and angle 2 is equal to angle 6 which makes it also 80 so you set 80 = 4x + 10 you first subtract the 10 and you have 70 = 4x and then divide by 4 and get x = 17.5
