Answer:
x = 7
Explanation:
The box around one of the angles indicates that the angle measures (90) degrees. The sum of angles in any triangle is (180) degrees. Using this knowledge, one can apply it here and find the measure of (x). Add all of the angles together and set them equal to (x). Simplify and use inverse operations,
(90) + (33) + (6x + 15) = 180
Simplify,
138 + 6x = 180
Inverse operations,
138 + 6x = 180
6x = 42
x = 7