x^2+28x-9=0

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Solution for x^2+28x-9=0 equation:


Simplifying
x2 + 28x + -9 = 0

Reorder the terms:
-9 + 28x + x2 = 0

Solving
-9 + 28x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '9' to each side of the equation.
-9 + 28x + 9 + x2 = 0 + 9

Reorder the terms:
-9 + 9 + 28x + x2 = 0 + 9

Combine like terms: -9 + 9 = 0
0 + 28x + x2 = 0 + 9
28x + x2 = 0 + 9

Combine like terms: 0 + 9 = 9
28x + x2 = 9

The x term is 28x.  Take half its coefficient (14).
Square it (196) and add it to both sides.

Add '196' to each side of the equation.
28x + 196 + x2 = 9 + 196

Reorder the terms:
196 + 28x + x2 = 9 + 196

Combine like terms: 9 + 196 = 205
196 + 28x + x2 = 205

Factor a perfect square on the left side:
(x + 14)(x + 14) = 205

Calculate the square root of the right side: 14.317821063

Break this problem into two subproblems by setting 
(x + 14) equal to 14.317821063 and -14.317821063.

Subproblem 1

x + 14 = 14.317821063 Simplifying x + 14 = 14.317821063 Reorder the terms: 14 + x = 14.317821063 Solving 14 + x = 14.317821063 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-14' to each side of the equation. 14 + -14 + x = 14.317821063 + -14 Combine like terms: 14 + -14 = 0 0 + x = 14.317821063 + -14 x = 14.317821063 + -14 Combine like terms: 14.317821063 + -14 = 0.317821063 x = 0.317821063 Simplifying x = 0.317821063

Subproblem 2

x + 14 = -14.317821063 Simplifying x + 14 = -14.317821063 Reorder the terms: 14 + x = -14.317821063 Solving 14 + x = -14.317821063 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-14' to each side of the equation. 14 + -14 + x = -14.317821063 + -14 Combine like terms: 14 + -14 = 0 0 + x = -14.317821063 + -14 x = -14.317821063 + -14 Combine like terms: -14.317821063 + -14 = -28.317821063 x = -28.317821063 Simplifying x = -28.317821063

Solution

The solution to the problem is based on the solutions from the subproblems. x = {0.317821063, -28.317821063}

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