Question 1084672
Two angles are complementary when they add up to {{{90}}} degrees.
Two angles are supplementary when they add up to {{{180}}} degrees.

{{{alpha+beta=90}}}........1)->  complement of {{{alpha}}} is {{{90-alpha}}}
{{{alpha+beta=180}}}........2)->supplement of {{{alpha}}} is {{{180-alpha}}}

if six times its complement is 12° less than it's supplement , we have

{{{6(90-alpha)+12=180-alpha}}}

{{{540-6alpha+12=180-alpha}}}

{{{540-180+12=6alpha-alpha}}}

{{{372=5alpha}}}

{{{372/5=alpha}}}

{{{highlight(alpha=74.4)}}}->the measure of your angle

then 
->  complement of {{{74.4}}} is {{{90-74.4=15.6}}}
->supplement of {{{74.4}}} is {{{180-74.4=105.6}}}

check:

{{{6(90-alpha)+12=180-alpha}}}

{{{6(15.6)+12=105.6}}}

{{{93.6+12=105.6}}}

{{{105.6=105.6}}}