7x^2-18x-16=0

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Solution for 7x^2-18x-16=0 equation:


Simplifying
7x2 + -18x + -16 = 0

Reorder the terms:
-16 + -18x + 7x2 = 0

Solving
-16 + -18x + 7x2 = 0

Solving for variable 'x'.

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

Divide each side by '7'.
-2.285714286 + -2.571428571x + x2 = 0

Move the constant term to the right:

Add '2.285714286' to each side of the equation.
-2.285714286 + -2.571428571x + 2.285714286 + x2 = 0 + 2.285714286

Reorder the terms:
-2.285714286 + 2.285714286 + -2.571428571x + x2 = 0 + 2.285714286

Combine like terms: -2.285714286 + 2.285714286 = 0.000000000
0.000000000 + -2.571428571x + x2 = 0 + 2.285714286
-2.571428571x + x2 = 0 + 2.285714286

Combine like terms: 0 + 2.285714286 = 2.285714286
-2.571428571x + x2 = 2.285714286

The x term is -2.571428571x.  Take half its coefficient (-1.285714286).
Square it (1.653061225) and add it to both sides.

Add '1.653061225' to each side of the equation.
-2.571428571x + 1.653061225 + x2 = 2.285714286 + 1.653061225

Reorder the terms:
1.653061225 + -2.571428571x + x2 = 2.285714286 + 1.653061225

Combine like terms: 2.285714286 + 1.653061225 = 3.938775511
1.653061225 + -2.571428571x + x2 = 3.938775511

Factor a perfect square on the left side:
(x + -1.285714286)(x + -1.285714286) = 3.938775511

Calculate the square root of the right side: 1.984634856

Break this problem into two subproblems by setting 
(x + -1.285714286) equal to 1.984634856 and -1.984634856.

Subproblem 1

x + -1.285714286 = 1.984634856 Simplifying x + -1.285714286 = 1.984634856 Reorder the terms: -1.285714286 + x = 1.984634856 Solving -1.285714286 + x = 1.984634856 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.285714286' to each side of the equation. -1.285714286 + 1.285714286 + x = 1.984634856 + 1.285714286 Combine like terms: -1.285714286 + 1.285714286 = 0.000000000 0.000000000 + x = 1.984634856 + 1.285714286 x = 1.984634856 + 1.285714286 Combine like terms: 1.984634856 + 1.285714286 = 3.270349142 x = 3.270349142 Simplifying x = 3.270349142

Subproblem 2

x + -1.285714286 = -1.984634856 Simplifying x + -1.285714286 = -1.984634856 Reorder the terms: -1.285714286 + x = -1.984634856 Solving -1.285714286 + x = -1.984634856 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.285714286' to each side of the equation. -1.285714286 + 1.285714286 + x = -1.984634856 + 1.285714286 Combine like terms: -1.285714286 + 1.285714286 = 0.000000000 0.000000000 + x = -1.984634856 + 1.285714286 x = -1.984634856 + 1.285714286 Combine like terms: -1.984634856 + 1.285714286 = -0.69892057 x = -0.69892057 Simplifying x = -0.69892057

Solution

The solution to the problem is based on the solutions from the subproblems. x = {3.270349142, -0.69892057}

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