(y^2)-(2y)-15=0

Solution for (y^2)-(2y)-15=0 equation:

Simplifying
(y2) + -1(2y) + -15 = 0
y2 + -1(2y) + -15 = 0

Remove parenthesis around (2y)
y2 + -1 * 2y + -15 = 0

Multiply -1 * 2
y2 + -2y + -15 = 0

Reorder the terms:
-15 + -2y + y2 = 0

Solving
-15 + -2y + y2 = 0

Solving for variable 'y'.

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

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

Simplifying
-3 + -1y = 0

Solving
-3 + -1y = 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 + -1y = 0 + 3

Combine like terms: -3 + 3 = 0
0 + -1y = 0 + 3
-1y = 0 + 3

Combine like terms: 0 + 3 = 3
-1y = 3

Divide each side by '-1'.
y = -3

Simplifying
y = -3
Subproblem 2
Set the factor '(5 + -1y)' equal to zero and attempt to solve:

Simplifying
5 + -1y = 0

Solving
5 + -1y = 0

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

Add '-5' to each side of the equation.
5 + -5 + -1y = 0 + -5

Combine like terms: 5 + -5 = 0
0 + -1y = 0 + -5
-1y = 0 + -5

Combine like terms: 0 + -5 = -5
-1y = -5

Divide each side by '-1'.
y = 5

Simplifying
y = 5
Solution
y = {-3, 5}