The measure of the supplement of an angle is 60 less than 3 times the measure of the complement of the angle. Find the measure of the angle.

if an angle measures x, then it's supplement is 180-x

similarly it's complement would be 90-x

then saying

"the supplement is 60 less than 3 times the complement"

180-x=3(90-x)-60

180-x=270-3x-60

180-x=210-3x

-x=30-3x

2x=30

x=15