7x^2-13x-28=0

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Solution for 7x^2-13x-28=0 equation:


Simplifying
7x2 + -13x + -28 = 0

Reorder the terms:
-28 + -13x + 7x2 = 0

Solving
-28 + -13x + 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'.
-4 + -1.857142857x + x2 = 0

Move the constant term to the right:

Add '4' to each side of the equation.
-4 + -1.857142857x + 4 + x2 = 0 + 4

Reorder the terms:
-4 + 4 + -1.857142857x + x2 = 0 + 4

Combine like terms: -4 + 4 = 0
0 + -1.857142857x + x2 = 0 + 4
-1.857142857x + x2 = 0 + 4

Combine like terms: 0 + 4 = 4
-1.857142857x + x2 = 4

The x term is -1.857142857x.  Take half its coefficient (-0.9285714285).
Square it (0.8622448978) and add it to both sides.

Add '0.8622448978' to each side of the equation.
-1.857142857x + 0.8622448978 + x2 = 4 + 0.8622448978

Reorder the terms:
0.8622448978 + -1.857142857x + x2 = 4 + 0.8622448978

Combine like terms: 4 + 0.8622448978 = 4.8622448978
0.8622448978 + -1.857142857x + x2 = 4.8622448978

Factor a perfect square on the left side:
(x + -0.9285714285)(x + -0.9285714285) = 4.8622448978

Calculate the square root of the right side: 2.205049863

Break this problem into two subproblems by setting 
(x + -0.9285714285) equal to 2.205049863 and -2.205049863.

Subproblem 1

x + -0.9285714285 = 2.205049863 Simplifying x + -0.9285714285 = 2.205049863 Reorder the terms: -0.9285714285 + x = 2.205049863 Solving -0.9285714285 + x = 2.205049863 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.9285714285' to each side of the equation. -0.9285714285 + 0.9285714285 + x = 2.205049863 + 0.9285714285 Combine like terms: -0.9285714285 + 0.9285714285 = 0.0000000000 0.0000000000 + x = 2.205049863 + 0.9285714285 x = 2.205049863 + 0.9285714285 Combine like terms: 2.205049863 + 0.9285714285 = 3.1336212915 x = 3.1336212915 Simplifying x = 3.1336212915

Subproblem 2

x + -0.9285714285 = -2.205049863 Simplifying x + -0.9285714285 = -2.205049863 Reorder the terms: -0.9285714285 + x = -2.205049863 Solving -0.9285714285 + x = -2.205049863 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.9285714285' to each side of the equation. -0.9285714285 + 0.9285714285 + x = -2.205049863 + 0.9285714285 Combine like terms: -0.9285714285 + 0.9285714285 = 0.0000000000 0.0000000000 + x = -2.205049863 + 0.9285714285 x = -2.205049863 + 0.9285714285 Combine like terms: -2.205049863 + 0.9285714285 = -1.2764784345 x = -1.2764784345 Simplifying x = -1.2764784345

Solution

The solution to the problem is based on the solutions from the subproblems. x = {3.1336212915, -1.2764784345}

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