9x^2+13x-4=0

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Solution for 9x^2+13x-4=0 equation:


Simplifying
9x2 + 13x + -4 = 0

Reorder the terms:
-4 + 13x + 9x2 = 0

Solving
-4 + 13x + 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'.
-0.4444444444 + 1.444444444x + x2 = 0

Move the constant term to the right:

Add '0.4444444444' to each side of the equation.
-0.4444444444 + 1.444444444x + 0.4444444444 + x2 = 0 + 0.4444444444

Reorder the terms:
-0.4444444444 + 0.4444444444 + 1.444444444x + x2 = 0 + 0.4444444444

Combine like terms: -0.4444444444 + 0.4444444444 = 0.0000000000
0.0000000000 + 1.444444444x + x2 = 0 + 0.4444444444
1.444444444x + x2 = 0 + 0.4444444444

Combine like terms: 0 + 0.4444444444 = 0.4444444444
1.444444444x + x2 = 0.4444444444

The x term is 1.444444444x.  Take half its coefficient (0.722222222).
Square it (0.5216049380) and add it to both sides.

Add '0.5216049380' to each side of the equation.
1.444444444x + 0.5216049380 + x2 = 0.4444444444 + 0.5216049380

Reorder the terms:
0.5216049380 + 1.444444444x + x2 = 0.4444444444 + 0.5216049380

Combine like terms: 0.4444444444 + 0.5216049380 = 0.9660493824
0.5216049380 + 1.444444444x + x2 = 0.9660493824

Factor a perfect square on the left side:
(x + 0.722222222)(x + 0.722222222) = 0.9660493824

Calculate the square root of the right side: 0.982878112

Break this problem into two subproblems by setting 
(x + 0.722222222) equal to 0.982878112 and -0.982878112.

Subproblem 1

x + 0.722222222 = 0.982878112 Simplifying x + 0.722222222 = 0.982878112 Reorder the terms: 0.722222222 + x = 0.982878112 Solving 0.722222222 + x = 0.982878112 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-0.722222222' to each side of the equation. 0.722222222 + -0.722222222 + x = 0.982878112 + -0.722222222 Combine like terms: 0.722222222 + -0.722222222 = 0.000000000 0.000000000 + x = 0.982878112 + -0.722222222 x = 0.982878112 + -0.722222222 Combine like terms: 0.982878112 + -0.722222222 = 0.26065589 x = 0.26065589 Simplifying x = 0.26065589

Subproblem 2

x + 0.722222222 = -0.982878112 Simplifying x + 0.722222222 = -0.982878112 Reorder the terms: 0.722222222 + x = -0.982878112 Solving 0.722222222 + x = -0.982878112 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-0.722222222' to each side of the equation. 0.722222222 + -0.722222222 + x = -0.982878112 + -0.722222222 Combine like terms: 0.722222222 + -0.722222222 = 0.000000000 0.000000000 + x = -0.982878112 + -0.722222222 x = -0.982878112 + -0.722222222 Combine like terms: -0.982878112 + -0.722222222 = -1.705100334 x = -1.705100334 Simplifying x = -1.705100334

Solution

The solution to the problem is based on the solutions from the subproblems. x = {0.26065589, -1.705100334}

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