Answer:
x = 21
Step-by-step explanation:
The angle marked (6x - 21) and the angle marked 75 are supplementary angles. This means that they add up to 180 (by definition). We know this because they lie on a straight line, and a straight line is always 180 degrees. Then we can set up an equation:
(6x - 21) + 75 = 180
6x + 54 = 180
6x = 180 - 54 = 126
x = 126/6 = 21
Thus, x = 21.
Hope this helps!
