d^2+2d-15=0

Solution for d^2+2d-15=0 equation:

Simplifying
d2 + 2d + -15 = 0

Reorder the terms:
-15 + 2d + d2 = 0

Solving
-15 + 2d + d2 = 0

Solving for variable 'd'.

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

Subproblem 1
Set the factor '(-5 + -1d)' equal to zero and attempt to solve:

Simplifying
-5 + -1d = 0

Solving
-5 + -1d = 0

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

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

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

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

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

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

Simplifying
3 + -1d = 0

Solving
3 + -1d = 0

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

Add '-3' to each side of the equation.
3 + -3 + -1d = 0 + -3

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

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

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

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