15y^2-21y-18=0

Solution for 15y^2-21y-18=0 equation:

Simplifying
15y2 + -21y + -18 = 0

Reorder the terms:
-18 + -21y + 15y2 = 0

Solving
-18 + -21y + 15y2 = 0

Solving for variable 'y'.

Factor out the Greatest Common Factor (GCF), '3'.
3(-6 + -7y + 5y2) = 0

Factor a trinomial.
3((-3 + -5y)(2 + -1y)) = 0

Ignore the factor 3.
Subproblem 1
Set the factor '(-3 + -5y)' equal to zero and attempt to solve:

Simplifying
-3 + -5y = 0

Solving
-3 + -5y = 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 + -5y = 0 + 3

Combine like terms: -3 + 3 = 0
0 + -5y = 0 + 3
-5y = 0 + 3

Combine like terms: 0 + 3 = 3
-5y = 3

Divide each side by '-5'.
y = -0.6

Simplifying
y = -0.6
Subproblem 2
Set the factor '(2 + -1y)' equal to zero and attempt to solve:

Simplifying
2 + -1y = 0

Solving
2 + -1y = 0

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

Add '-2' to each side of the equation.
2 + -2 + -1y = 0 + -2

Combine like terms: 2 + -2 = 0
0 + -1y = 0 + -2
-1y = 0 + -2

Combine like terms: 0 + -2 = -2
-1y = -2

Divide each side by '-1'.
y = 2

Simplifying
y = 2
Solution
y = {-0.6, 2}