x^2+18x-7=0

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Solution for x^2+18x-7=0 equation:


Simplifying
x2 + 18x + -7 = 0

Reorder the terms:
-7 + 18x + x2 = 0

Solving
-7 + 18x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '7' to each side of the equation.
-7 + 18x + 7 + x2 = 0 + 7

Reorder the terms:
-7 + 7 + 18x + x2 = 0 + 7

Combine like terms: -7 + 7 = 0
0 + 18x + x2 = 0 + 7
18x + x2 = 0 + 7

Combine like terms: 0 + 7 = 7
18x + x2 = 7

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 = 7 + 81

Reorder the terms:
81 + 18x + x2 = 7 + 81

Combine like terms: 7 + 81 = 88
81 + 18x + x2 = 88

Factor a perfect square on the left side:
(x + 9)(x + 9) = 88

Calculate the square root of the right side: 9.38083152

Break this problem into two subproblems by setting 
(x + 9) equal to 9.38083152 and -9.38083152.

Subproblem 1

x + 9 = 9.38083152 Simplifying x + 9 = 9.38083152 Reorder the terms: 9 + x = 9.38083152 Solving 9 + x = 9.38083152 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 = 9.38083152 + -9 Combine like terms: 9 + -9 = 0 0 + x = 9.38083152 + -9 x = 9.38083152 + -9 Combine like terms: 9.38083152 + -9 = 0.38083152 x = 0.38083152 Simplifying x = 0.38083152

Subproblem 2

x + 9 = -9.38083152 Simplifying x + 9 = -9.38083152 Reorder the terms: 9 + x = -9.38083152 Solving 9 + x = -9.38083152 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 = -9.38083152 + -9 Combine like terms: 9 + -9 = 0 0 + x = -9.38083152 + -9 x = -9.38083152 + -9 Combine like terms: -9.38083152 + -9 = -18.38083152 x = -18.38083152 Simplifying x = -18.38083152

Solution

The solution to the problem is based on the solutions from the subproblems. x = {0.38083152, -18.38083152}

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