x = 59
Because opposite angles are congruent, this is an isosceles trapezoid. Meaning x and 2x + 3 equal 180, half of the total interior angle. If you out that into equation form: x + 2x + 3 = 180. After combining like terms: 3x + 3 = 180. Then subtract 3 from both sides: 3x = 177. 177/3 = 59. x = 59.