supplementary angles add up to 180 degrees.
so if u have one angle " a ", then its supplementary angle is " 180 - a "
a = 5(180 - a)
a = 900 - 5a
5a + a = 900
6a = 900
a = 900/6
a = 150
and its supplementary angle is : 180 - a.....180 - 150 = 30 degrees
so ur answer is : < a = 150 and its supplement angle is 30