Hi FailedOnce,

I must assume you know the definition of complementary and supplementary angles.

1) Let x = the measure of the angle

Let 2x + 12 = the measure of its supplement

x + 2x + 12 = 180

2) Let x = the angle

Let 90 - x = its complement

Let 180 -x = its supplement

180 - x = 6(90 - x)