Two angles are supplementary. one angle measures 2 x , and the other angle measures 3 x - 15. which equation can you use to find the measure of each angle? 2 x + 3 x - 15 = 90° 2 x - 3 x - 15 = 180° 2 x - 3 x - 15 = 90° 2 x + 3 x - 15 = 180