-7x^2+8x+7=0

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


Simplifying
-7x2 + 8x + 7 = 0

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

Solving
7 + 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'.
-1 + -1.142857143x + x2 = 0

Move the constant term to the right:

Add '1' to each side of the equation.
-1 + -1.142857143x + 1 + x2 = 0 + 1

Reorder the terms:
-1 + 1 + -1.142857143x + x2 = 0 + 1

Combine like terms: -1 + 1 = 0
0 + -1.142857143x + x2 = 0 + 1
-1.142857143x + x2 = 0 + 1

Combine like terms: 0 + 1 = 1
-1.142857143x + x2 = 1

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 = 1 + 0.3265306123

Reorder the terms:
0.3265306123 + -1.142857143x + x2 = 1 + 0.3265306123

Combine like terms: 1 + 0.3265306123 = 1.3265306123
0.3265306123 + -1.142857143x + x2 = 1.3265306123

Factor a perfect square on the left side:
(x + -0.5714285715)(x + -0.5714285715) = 1.3265306123

Calculate the square root of the right side: 1.151751107

Break this problem into two subproblems by setting 
(x + -0.5714285715) equal to 1.151751107 and -1.151751107.

Subproblem 1

x + -0.5714285715 = 1.151751107 Simplifying x + -0.5714285715 = 1.151751107 Reorder the terms: -0.5714285715 + x = 1.151751107 Solving -0.5714285715 + x = 1.151751107 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 = 1.151751107 + 0.5714285715 Combine like terms: -0.5714285715 + 0.5714285715 = 0.0000000000 0.0000000000 + x = 1.151751107 + 0.5714285715 x = 1.151751107 + 0.5714285715 Combine like terms: 1.151751107 + 0.5714285715 = 1.7231796785 x = 1.7231796785 Simplifying x = 1.7231796785

Subproblem 2

x + -0.5714285715 = -1.151751107 Simplifying x + -0.5714285715 = -1.151751107 Reorder the terms: -0.5714285715 + x = -1.151751107 Solving -0.5714285715 + x = -1.151751107 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 = -1.151751107 + 0.5714285715 Combine like terms: -0.5714285715 + 0.5714285715 = 0.0000000000 0.0000000000 + x = -1.151751107 + 0.5714285715 x = -1.151751107 + 0.5714285715 Combine like terms: -1.151751107 + 0.5714285715 = -0.5803225355 x = -0.5803225355 Simplifying x = -0.5803225355

Solution

The solution to the problem is based on the solutions from the subproblems. x = {1.7231796785, -0.5803225355}

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