A linear pair is a pair of adjacent angles formed when two lines intersect.
Linear pair angles add up to 180 degrees because they lie on a straight line.
Let x = smaller angle
Let 5x - 18 = bigger angle
x + 5x -18 = 180
6x = 198
x = 198/6
x = 33
The smaller angle is 33 degrees and the bigger is 147 degrees