9x^2-4x-1=0

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Solution for 9x^2-4x-1=0 equation:


Simplifying
9x2 + -4x + -1 = 0

Reorder the terms:
-1 + -4x + 9x2 = 0

Solving
-1 + -4x + 9x2 = 0

Solving for variable 'x'.

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

Divide each side by '9'.
-0.1111111111 + -0.4444444444x + x2 = 0

Move the constant term to the right:

Add '0.1111111111' to each side of the equation.
-0.1111111111 + -0.4444444444x + 0.1111111111 + x2 = 0 + 0.1111111111

Reorder the terms:
-0.1111111111 + 0.1111111111 + -0.4444444444x + x2 = 0 + 0.1111111111

Combine like terms: -0.1111111111 + 0.1111111111 = 0.0000000000
0.0000000000 + -0.4444444444x + x2 = 0 + 0.1111111111
-0.4444444444x + x2 = 0 + 0.1111111111

Combine like terms: 0 + 0.1111111111 = 0.1111111111
-0.4444444444x + x2 = 0.1111111111

The x term is -0.4444444444x.  Take half its coefficient (-0.2222222222).
Square it (0.04938271604) and add it to both sides.

Add '0.04938271604' to each side of the equation.
-0.4444444444x + 0.04938271604 + x2 = 0.1111111111 + 0.04938271604

Reorder the terms:
0.04938271604 + -0.4444444444x + x2 = 0.1111111111 + 0.04938271604

Combine like terms: 0.1111111111 + 0.04938271604 = 0.16049382714
0.04938271604 + -0.4444444444x + x2 = 0.16049382714

Factor a perfect square on the left side:
(x + -0.2222222222)(x + -0.2222222222) = 0.16049382714

Calculate the square root of the right side: 0.400616808

Break this problem into two subproblems by setting 
(x + -0.2222222222) equal to 0.400616808 and -0.400616808.

Subproblem 1

x + -0.2222222222 = 0.400616808 Simplifying x + -0.2222222222 = 0.400616808 Reorder the terms: -0.2222222222 + x = 0.400616808 Solving -0.2222222222 + x = 0.400616808 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.2222222222' to each side of the equation. -0.2222222222 + 0.2222222222 + x = 0.400616808 + 0.2222222222 Combine like terms: -0.2222222222 + 0.2222222222 = 0.0000000000 0.0000000000 + x = 0.400616808 + 0.2222222222 x = 0.400616808 + 0.2222222222 Combine like terms: 0.400616808 + 0.2222222222 = 0.6228390302 x = 0.6228390302 Simplifying x = 0.6228390302

Subproblem 2

x + -0.2222222222 = -0.400616808 Simplifying x + -0.2222222222 = -0.400616808 Reorder the terms: -0.2222222222 + x = -0.400616808 Solving -0.2222222222 + x = -0.400616808 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.2222222222' to each side of the equation. -0.2222222222 + 0.2222222222 + x = -0.400616808 + 0.2222222222 Combine like terms: -0.2222222222 + 0.2222222222 = 0.0000000000 0.0000000000 + x = -0.400616808 + 0.2222222222 x = -0.400616808 + 0.2222222222 Combine like terms: -0.400616808 + 0.2222222222 = -0.1783945858 x = -0.1783945858 Simplifying x = -0.1783945858

Solution

The solution to the problem is based on the solutions from the subproblems. x = {0.6228390302, -0.1783945858}

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