Take into account that adjacent angle to (5x -2) and above line n is congruent to angle (5x + 2). It means that angles (5x - 2) and (5x + 2) are supplementary, that is, they add up 180 degrees.
Then, you can write:
(5x + 2) + (5x- 2) = 180
5x + 2 + 5x - 2 = 180
5x + 5x + 2 - 2 = 180
10x = 180
x = 180/10
x = 18
Hence, the value of x is 18