= + 25. It is your basic and starting equation, which follows the problem's description. To solve this equation, multiply both sides by 6. You will get 3x = 2*(180-x) + 150, 3x = 360 - 2x + 150, 3x + 2x = 360 + 150 5x = 510 x = = 102 degrees. ANSWER. The angle's measure is 102 degrees. Its supplement measure is 180-102 = 78 degrees.