Find all solutions to the equation y^2-36=5y

To solve:
first, bring everything to one side so we have a quadratic equation.
y^2-5y-36=0
then factor.
(y-9)(y+4)=0
put each value to zero.
y-9=0
y=9
y+4=0
y=-4

Answers: y=9, and y=-4

This is a quadratic equation 
y^2 - 5y - 36 = 0
Factoring 
(y - 9)(y + 4) = 0

y-9 = 0 giving y = 9  or y+4 = 0 giving y = -4

Solution set is {-4, 9}

The expression -8/-4 has the same value as -18/-9.