-90-9y+y^2=0

Solution for -90-9y+y^2=0 equation:

Simplifying
-90 + -9y + y2 = 0

Solving
-90 + -9y + y2 = 0

Solving for variable 'y'.

Factor a trinomial.
(-6 + -1y)(15 + -1y) = 0

Subproblem 1
Set the factor '(-6 + -1y)' equal to zero and attempt to solve:

Simplifying
-6 + -1y = 0

Solving
-6 + -1y = 0

Move all terms containing y to the left, all other terms to the right.

Add '6' to each side of the equation.
-6 + 6 + -1y = 0 + 6

Combine like terms: -6 + 6 = 0
0 + -1y = 0 + 6
-1y = 0 + 6

Combine like terms: 0 + 6 = 6
-1y = 6

Divide each side by '-1'.
y = -6

Simplifying
y = -6
Subproblem 2
Set the factor '(15 + -1y)' equal to zero and attempt to solve:

Simplifying
15 + -1y = 0

Solving
15 + -1y = 0

Move all terms containing y to the left, all other terms to the right.

Add '-15' to each side of the equation.
15 + -15 + -1y = 0 + -15

Combine like terms: 15 + -15 = 0
0 + -1y = 0 + -15
-1y = 0 + -15

Combine like terms: 0 + -15 = -15
-1y = -15

Divide each side by '-1'.
y = 15

Simplifying
y = 15
Solution
y = {-6, 15}