Question 831227


First we need to translate what we're told into equation form.  I'll call the angles x and 180-x (supplementary angles total 180):
3x = (180 - x) + 72 (product of 8 and 9)

First remove the grouping symbols:
3x = 180 - x + 72

Combine the constants:
3x = 252 - x

Add x to eliminate it from the right side:
4x = 252

Divide by 4:
x = 63

This is one angle; the other is its difference from 180, or 117.
So your supplementary angles are 117 and 63.

Check:
3(63) = (180 - 63) + 72
189 =? 117+72
189 = 189 {{{check}}}