7x^2-8x-65=0

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Solution for 7x^2-8x-65=0 equation:


Simplifying
7x2 + -8x + -65 = 0

Reorder the terms:
-65 + -8x + 7x2 = 0

Solving
-65 + -8x + 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'.
-9.285714286 + -1.142857143x + x2 = 0

Move the constant term to the right:

Add '9.285714286' to each side of the equation.
-9.285714286 + -1.142857143x + 9.285714286 + x2 = 0 + 9.285714286

Reorder the terms:
-9.285714286 + 9.285714286 + -1.142857143x + x2 = 0 + 9.285714286

Combine like terms: -9.285714286 + 9.285714286 = 0.000000000
0.000000000 + -1.142857143x + x2 = 0 + 9.285714286
-1.142857143x + x2 = 0 + 9.285714286

Combine like terms: 0 + 9.285714286 = 9.285714286
-1.142857143x + x2 = 9.285714286

The x term is -1.142857143x.  Take half its coefficient (-0.5714285715).
Square it (0.3265306123) and add it to both sides.

Add '0.3265306123' to each side of the equation.
-1.142857143x + 0.3265306123 + x2 = 9.285714286 + 0.3265306123

Reorder the terms:
0.3265306123 + -1.142857143x + x2 = 9.285714286 + 0.3265306123

Combine like terms: 9.285714286 + 0.3265306123 = 9.6122448983
0.3265306123 + -1.142857143x + x2 = 9.6122448983

Factor a perfect square on the left side:
(x + -0.5714285715)(x + -0.5714285715) = 9.6122448983

Calculate the square root of the right side: 3.100362059

Break this problem into two subproblems by setting 
(x + -0.5714285715) equal to 3.100362059 and -3.100362059.

Subproblem 1

x + -0.5714285715 = 3.100362059 Simplifying x + -0.5714285715 = 3.100362059 Reorder the terms: -0.5714285715 + x = 3.100362059 Solving -0.5714285715 + x = 3.100362059 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.5714285715' to each side of the equation. -0.5714285715 + 0.5714285715 + x = 3.100362059 + 0.5714285715 Combine like terms: -0.5714285715 + 0.5714285715 = 0.0000000000 0.0000000000 + x = 3.100362059 + 0.5714285715 x = 3.100362059 + 0.5714285715 Combine like terms: 3.100362059 + 0.5714285715 = 3.6717906305 x = 3.6717906305 Simplifying x = 3.6717906305

Subproblem 2

x + -0.5714285715 = -3.100362059 Simplifying x + -0.5714285715 = -3.100362059 Reorder the terms: -0.5714285715 + x = -3.100362059 Solving -0.5714285715 + x = -3.100362059 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.5714285715' to each side of the equation. -0.5714285715 + 0.5714285715 + x = -3.100362059 + 0.5714285715 Combine like terms: -0.5714285715 + 0.5714285715 = 0.0000000000 0.0000000000 + x = -3.100362059 + 0.5714285715 x = -3.100362059 + 0.5714285715 Combine like terms: -3.100362059 + 0.5714285715 = -2.5289334875 x = -2.5289334875 Simplifying x = -2.5289334875

Solution

The solution to the problem is based on the solutions from the subproblems. x = {3.6717906305, -2.5289334875}

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