7b^2-4b-56=0

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Solution for 7b^2-4b-56=0 equation:


Simplifying
7b2 + -4b + -56 = 0

Reorder the terms:
-56 + -4b + 7b2 = 0

Solving
-56 + -4b + 7b2 = 0

Solving for variable 'b'.

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

Divide each side by '7'.
-8 + -0.5714285714b + b2 = 0

Move the constant term to the right:

Add '8' to each side of the equation.
-8 + -0.5714285714b + 8 + b2 = 0 + 8

Reorder the terms:
-8 + 8 + -0.5714285714b + b2 = 0 + 8

Combine like terms: -8 + 8 = 0
0 + -0.5714285714b + b2 = 0 + 8
-0.5714285714b + b2 = 0 + 8

Combine like terms: 0 + 8 = 8
-0.5714285714b + b2 = 8

The b term is -0.5714285714b.  Take half its coefficient (-0.2857142857).
Square it (0.08163265305) and add it to both sides.

Add '0.08163265305' to each side of the equation.
-0.5714285714b + 0.08163265305 + b2 = 8 + 0.08163265305

Reorder the terms:
0.08163265305 + -0.5714285714b + b2 = 8 + 0.08163265305

Combine like terms: 8 + 0.08163265305 = 8.08163265305
0.08163265305 + -0.5714285714b + b2 = 8.08163265305

Factor a perfect square on the left side:
(b + -0.2857142857)(b + -0.2857142857) = 8.08163265305

Calculate the square root of the right side: 2.842821249

Break this problem into two subproblems by setting 
(b + -0.2857142857) equal to 2.842821249 and -2.842821249.

Subproblem 1

b + -0.2857142857 = 2.842821249 Simplifying b + -0.2857142857 = 2.842821249 Reorder the terms: -0.2857142857 + b = 2.842821249 Solving -0.2857142857 + b = 2.842821249 Solving for variable 'b'. Move all terms containing b to the left, all other terms to the right. Add '0.2857142857' to each side of the equation. -0.2857142857 + 0.2857142857 + b = 2.842821249 + 0.2857142857 Combine like terms: -0.2857142857 + 0.2857142857 = 0.0000000000 0.0000000000 + b = 2.842821249 + 0.2857142857 b = 2.842821249 + 0.2857142857 Combine like terms: 2.842821249 + 0.2857142857 = 3.1285355347 b = 3.1285355347 Simplifying b = 3.1285355347

Subproblem 2

b + -0.2857142857 = -2.842821249 Simplifying b + -0.2857142857 = -2.842821249 Reorder the terms: -0.2857142857 + b = -2.842821249 Solving -0.2857142857 + b = -2.842821249 Solving for variable 'b'. Move all terms containing b to the left, all other terms to the right. Add '0.2857142857' to each side of the equation. -0.2857142857 + 0.2857142857 + b = -2.842821249 + 0.2857142857 Combine like terms: -0.2857142857 + 0.2857142857 = 0.0000000000 0.0000000000 + b = -2.842821249 + 0.2857142857 b = -2.842821249 + 0.2857142857 Combine like terms: -2.842821249 + 0.2857142857 = -2.5571069633 b = -2.5571069633 Simplifying b = -2.5571069633

Solution

The solution to the problem is based on the solutions from the subproblems. b = {3.1285355347, -2.5571069633}

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