Answer:
x = 8
Step-by-step explanation:
Supplementary angles add up to 180 degrees to make a straight line.
The red square in one of them indicates that it is 90 degrees on their side which means that it is 90 degrees on the other where (6x+2) and 40 degrees are.
(6x+2) + 40 = 90
6x + 42 = 90
6x = 48
x = 8
