x^2+18x=-4

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Solution for x^2+18x=-4 equation:


Simplifying
x2 + 18x = -4

Reorder the terms:
18x + x2 = -4

Solving
18x + x2 = -4

Solving for variable 'x'.

Reorder the terms:
4 + 18x + x2 = -4 + 4

Combine like terms: -4 + 4 = 0
4 + 18x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-4' to each side of the equation.
4 + 18x + -4 + x2 = 0 + -4

Reorder the terms:
4 + -4 + 18x + x2 = 0 + -4

Combine like terms: 4 + -4 = 0
0 + 18x + x2 = 0 + -4
18x + x2 = 0 + -4

Combine like terms: 0 + -4 = -4
18x + x2 = -4

The x term is 18x.  Take half its coefficient (9).
Square it (81) and add it to both sides.

Add '81' to each side of the equation.
18x + 81 + x2 = -4 + 81

Reorder the terms:
81 + 18x + x2 = -4 + 81

Combine like terms: -4 + 81 = 77
81 + 18x + x2 = 77

Factor a perfect square on the left side:
(x + 9)(x + 9) = 77

Calculate the square root of the right side: 8.774964387

Break this problem into two subproblems by setting 
(x + 9) equal to 8.774964387 and -8.774964387.

Subproblem 1

x + 9 = 8.774964387 Simplifying x + 9 = 8.774964387 Reorder the terms: 9 + x = 8.774964387 Solving 9 + x = 8.774964387 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-9' to each side of the equation. 9 + -9 + x = 8.774964387 + -9 Combine like terms: 9 + -9 = 0 0 + x = 8.774964387 + -9 x = 8.774964387 + -9 Combine like terms: 8.774964387 + -9 = -0.225035613 x = -0.225035613 Simplifying x = -0.225035613

Subproblem 2

x + 9 = -8.774964387 Simplifying x + 9 = -8.774964387 Reorder the terms: 9 + x = -8.774964387 Solving 9 + x = -8.774964387 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-9' to each side of the equation. 9 + -9 + x = -8.774964387 + -9 Combine like terms: 9 + -9 = 0 0 + x = -8.774964387 + -9 x = -8.774964387 + -9 Combine like terms: -8.774964387 + -9 = -17.774964387 x = -17.774964387 Simplifying x = -17.774964387

Solution

The solution to the problem is based on the solutions from the subproblems. x = {-0.225035613, -17.774964387}

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