the correct question is
Suppose you know that S angle and Y angle are complementary, and that angle S=5(angle Y)- 180 degrees. What is the value of angle Y?
we know that
S angle and Y angle are complementary
so
S+Y=90-------> S=90-Y------> equation 1
and
S=5Y-180----> equation 2
equate equation 1 and equation 2
90-Y=5Y-180------> 5Y+Y=180+90-----> 6Y=270-----> Y=45°
S=5*45-180-----> S=45°
the answer is
Y=45°