x(2x+5)=x-15

Solution for x(2x+5)=x-15 equation:

Simplifying
x(2x + 5) = x + -15

Reorder the terms:
x(5 + 2x) = x + -15
(5 * x + 2x * x) = x + -15
(5x + 2x2) = x + -15

Reorder the terms:
5x + 2x2 = -15 + x

Solving
5x + 2x2 = -15 + x

Solving for variable 'x'.

Reorder the terms:
15 + 5x + -1x + 2x2 = -15 + x + 15 + -1x

Combine like terms: 5x + -1x = 4x
15 + 4x + 2x2 = -15 + x + 15 + -1x

Reorder the terms:
15 + 4x + 2x2 = -15 + 15 + x + -1x

Combine like terms: -15 + 15 = 0
15 + 4x + 2x2 = 0 + x + -1x
15 + 4x + 2x2 = x + -1x

Combine like terms: x + -1x = 0
15 + 4x + 2x2 = 0

Begin completing the square.  Divide all terms by
2 the coefficient of the squared term: 

Divide each side by '2'.
7.5 + 2x + x2 = 0

Move the constant term to the right:

Add '-7.5' to each side of the equation.
7.5 + 2x + -7.5 + x2 = 0 + -7.5

Reorder the terms:
7.5 + -7.5 + 2x + x2 = 0 + -7.5

Combine like terms: 7.5 + -7.5 = 0.0
0.0 + 2x + x2 = 0 + -7.5
2x + x2 = 0 + -7.5

Combine like terms: 0 + -7.5 = -7.5
2x + x2 = -7.5

The x term is 2x.  Take half its coefficient (1).
Square it (1) and add it to both sides.

Add '1' to each side of the equation.
2x + 1 + x2 = -7.5 + 1

Reorder the terms:
1 + 2x + x2 = -7.5 + 1

Combine like terms: -7.5 + 1 = -6.5
1 + 2x + x2 = -6.5

Factor a perfect square on the left side:
(x + 1)(x + 1) = -6.5

Can't calculate square root of the right side.

The solution to this equation could not be determined.