-y^2-9y-18=0

Solution for -y^2-9y-18=0 equation:

Simplifying
-1y2 + -9y + -18 = 0

Reorder the terms:
-18 + -9y + -1y2 = 0

Solving
-18 + -9y + -1y2 = 0

Solving for variable 'y'.

Factor out the Greatest Common Factor (GCF), '-1'.
-1(18 + 9y + y2) = 0

Factor a trinomial.
-1((6 + y)(3 + y)) = 0

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

Simplifying
6 + y = 0

Solving
6 + y = 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 + y = 0 + -6

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

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

Simplifying
y = -6
Subproblem 2
Set the factor '(3 + y)' equal to zero and attempt to solve:

Simplifying
3 + y = 0

Solving
3 + y = 0

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

Add '-3' to each side of the equation.
3 + -3 + y = 0 + -3

Combine like terms: 3 + -3 = 0
0 + y = 0 + -3
y = 0 + -3

Combine like terms: 0 + -3 = -3
y = -3

Simplifying
y = -3
Solution
y = {-6, -3}