9x^2+7x-8=0

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Solution for 9x^2+7x-8=0 equation:


Simplifying
9x2 + 7x + -8 = 0

Reorder the terms:
-8 + 7x + 9x2 = 0

Solving
-8 + 7x + 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'.
-0.8888888889 + 0.7777777778x + x2 = 0

Move the constant term to the right:

Add '0.8888888889' to each side of the equation.
-0.8888888889 + 0.7777777778x + 0.8888888889 + x2 = 0 + 0.8888888889

Reorder the terms:
-0.8888888889 + 0.8888888889 + 0.7777777778x + x2 = 0 + 0.8888888889

Combine like terms: -0.8888888889 + 0.8888888889 = 0.0000000000
0.0000000000 + 0.7777777778x + x2 = 0 + 0.8888888889
0.7777777778x + x2 = 0 + 0.8888888889

Combine like terms: 0 + 0.8888888889 = 0.8888888889
0.7777777778x + x2 = 0.8888888889

The x term is 0.7777777778x.  Take half its coefficient (0.3888888889).
Square it (0.1512345679) and add it to both sides.

Add '0.1512345679' to each side of the equation.
0.7777777778x + 0.1512345679 + x2 = 0.8888888889 + 0.1512345679

Reorder the terms:
0.1512345679 + 0.7777777778x + x2 = 0.8888888889 + 0.1512345679

Combine like terms: 0.8888888889 + 0.1512345679 = 1.0401234568
0.1512345679 + 0.7777777778x + x2 = 1.0401234568

Factor a perfect square on the left side:
(x + 0.3888888889)(x + 0.3888888889) = 1.0401234568

Calculate the square root of the right side: 1.019864431

Break this problem into two subproblems by setting 
(x + 0.3888888889) equal to 1.019864431 and -1.019864431.

Subproblem 1

x + 0.3888888889 = 1.019864431 Simplifying x + 0.3888888889 = 1.019864431 Reorder the terms: 0.3888888889 + x = 1.019864431 Solving 0.3888888889 + x = 1.019864431 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-0.3888888889' to each side of the equation. 0.3888888889 + -0.3888888889 + x = 1.019864431 + -0.3888888889 Combine like terms: 0.3888888889 + -0.3888888889 = 0.0000000000 0.0000000000 + x = 1.019864431 + -0.3888888889 x = 1.019864431 + -0.3888888889 Combine like terms: 1.019864431 + -0.3888888889 = 0.6309755421 x = 0.6309755421 Simplifying x = 0.6309755421

Subproblem 2

x + 0.3888888889 = -1.019864431 Simplifying x + 0.3888888889 = -1.019864431 Reorder the terms: 0.3888888889 + x = -1.019864431 Solving 0.3888888889 + x = -1.019864431 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-0.3888888889' to each side of the equation. 0.3888888889 + -0.3888888889 + x = -1.019864431 + -0.3888888889 Combine like terms: 0.3888888889 + -0.3888888889 = 0.0000000000 0.0000000000 + x = -1.019864431 + -0.3888888889 x = -1.019864431 + -0.3888888889 Combine like terms: -1.019864431 + -0.3888888889 = -1.4087533199 x = -1.4087533199 Simplifying x = -1.4087533199

Solution

The solution to the problem is based on the solutions from the subproblems. x = {0.6309755421, -1.4087533199}

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