x^2+15x=-3

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Solution for x^2+15x=-3 equation:


Simplifying
x2 + 15x = -3

Reorder the terms:
15x + x2 = -3

Solving
15x + x2 = -3

Solving for variable 'x'.

Reorder the terms:
3 + 15x + x2 = -3 + 3

Combine like terms: -3 + 3 = 0
3 + 15x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-3' to each side of the equation.
3 + 15x + -3 + x2 = 0 + -3

Reorder the terms:
3 + -3 + 15x + x2 = 0 + -3

Combine like terms: 3 + -3 = 0
0 + 15x + x2 = 0 + -3
15x + x2 = 0 + -3

Combine like terms: 0 + -3 = -3
15x + x2 = -3

The x term is 15x.  Take half its coefficient (7.5).
Square it (56.25) and add it to both sides.

Add '56.25' to each side of the equation.
15x + 56.25 + x2 = -3 + 56.25

Reorder the terms:
56.25 + 15x + x2 = -3 + 56.25

Combine like terms: -3 + 56.25 = 53.25
56.25 + 15x + x2 = 53.25

Factor a perfect square on the left side:
(x + 7.5)(x + 7.5) = 53.25

Calculate the square root of the right side: 7.29725976

Break this problem into two subproblems by setting 
(x + 7.5) equal to 7.29725976 and -7.29725976.

Subproblem 1

x + 7.5 = 7.29725976 Simplifying x + 7.5 = 7.29725976 Reorder the terms: 7.5 + x = 7.29725976 Solving 7.5 + x = 7.29725976 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-7.5' to each side of the equation. 7.5 + -7.5 + x = 7.29725976 + -7.5 Combine like terms: 7.5 + -7.5 = 0.0 0.0 + x = 7.29725976 + -7.5 x = 7.29725976 + -7.5 Combine like terms: 7.29725976 + -7.5 = -0.20274024 x = -0.20274024 Simplifying x = -0.20274024

Subproblem 2

x + 7.5 = -7.29725976 Simplifying x + 7.5 = -7.29725976 Reorder the terms: 7.5 + x = -7.29725976 Solving 7.5 + x = -7.29725976 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-7.5' to each side of the equation. 7.5 + -7.5 + x = -7.29725976 + -7.5 Combine like terms: 7.5 + -7.5 = 0.0 0.0 + x = -7.29725976 + -7.5 x = -7.29725976 + -7.5 Combine like terms: -7.29725976 + -7.5 = -14.79725976 x = -14.79725976 Simplifying x = -14.79725976

Solution

The solution to the problem is based on the solutions from the subproblems. x = {-0.20274024, -14.79725976}

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