x = the angle
90 - x = complement {complementary angles add up to 90°}
180 - x = supplement {supplementary angles add up to 180°}
180 - x = 5(90 - x) {supplement is 5 times its complement}
180 - x = 450 - 5x {used distributive property}
-x = 270 - 5x {subtracted 180 from both sides}
4x = 270 {added 5x to both sides}
x = 67.5
