x(x+1)-x-15=0

Solution for x(x+1)-x-15=0 equation:

Simplifying
x(x + 1) + -1x + -15 = 0

Reorder the terms:
x(1 + x) + -1x + -15 = 0
(1 * x + x * x) + -1x + -15 = 0
(1x + x2) + -1x + -15 = 0

Reorder the terms:
-15 + 1x + -1x + x2 = 0

Combine like terms: 1x + -1x = 0
-15 + 0 + x2 = 0
-15 + x2 = 0

Solving
-15 + x2 = 0

Solving for variable 'x'.

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

Add '15' to each side of the equation.
-15 + 15 + x2 = 0 + 15

Combine like terms: -15 + 15 = 0
0 + x2 = 0 + 15
x2 = 0 + 15

Combine like terms: 0 + 15 = 15
x2 = 15

Simplifying
x2 = 15

Take the square root of each side:
x = {-3.872983346, 3.872983346}