The exterior angle is = to the 2 interior angles. 83 = (9x + 4) + (4x + 1) Remove the brackets 83 = 9x + 4 + 4x + 1 Group the like terms 83 = 9x + 4x + 4 + 1 Add the like terms. 83 = 13x + 5 Subtract 5 from both sides. 78 = 13x Divide by 13 78 / 13 = x x = 6
So They want the angles 9x + 4 = 9*6 + 4 = 58 4x + 1 = 4*6 + 1 = 25
When you add these two together you should get 83. Do you?
