7x^2-5x-84=

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Solution for 7x^2-5x-84= equation:


Simplifying
7x2 + -5x + -84 = 0

Reorder the terms:
-84 + -5x + 7x2 = 0

Solving
-84 + -5x + 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'.
-12 + -0.7142857143x + x2 = 0

Move the constant term to the right:

Add '12' to each side of the equation.
-12 + -0.7142857143x + 12 + x2 = 0 + 12

Reorder the terms:
-12 + 12 + -0.7142857143x + x2 = 0 + 12

Combine like terms: -12 + 12 = 0
0 + -0.7142857143x + x2 = 0 + 12
-0.7142857143x + x2 = 0 + 12

Combine like terms: 0 + 12 = 12
-0.7142857143x + x2 = 12

The x term is -0.7142857143x.  Take half its coefficient (-0.3571428572).
Square it (0.1275510204) and add it to both sides.

Add '0.1275510204' to each side of the equation.
-0.7142857143x + 0.1275510204 + x2 = 12 + 0.1275510204

Reorder the terms:
0.1275510204 + -0.7142857143x + x2 = 12 + 0.1275510204

Combine like terms: 12 + 0.1275510204 = 12.1275510204
0.1275510204 + -0.7142857143x + x2 = 12.1275510204

Factor a perfect square on the left side:
(x + -0.3571428572)(x + -0.3571428572) = 12.1275510204

Calculate the square root of the right side: 3.482463355

Break this problem into two subproblems by setting 
(x + -0.3571428572) equal to 3.482463355 and -3.482463355.

Subproblem 1

x + -0.3571428572 = 3.482463355 Simplifying x + -0.3571428572 = 3.482463355 Reorder the terms: -0.3571428572 + x = 3.482463355 Solving -0.3571428572 + x = 3.482463355 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.3571428572' to each side of the equation. -0.3571428572 + 0.3571428572 + x = 3.482463355 + 0.3571428572 Combine like terms: -0.3571428572 + 0.3571428572 = 0.0000000000 0.0000000000 + x = 3.482463355 + 0.3571428572 x = 3.482463355 + 0.3571428572 Combine like terms: 3.482463355 + 0.3571428572 = 3.8396062122 x = 3.8396062122 Simplifying x = 3.8396062122

Subproblem 2

x + -0.3571428572 = -3.482463355 Simplifying x + -0.3571428572 = -3.482463355 Reorder the terms: -0.3571428572 + x = -3.482463355 Solving -0.3571428572 + x = -3.482463355 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.3571428572' to each side of the equation. -0.3571428572 + 0.3571428572 + x = -3.482463355 + 0.3571428572 Combine like terms: -0.3571428572 + 0.3571428572 = 0.0000000000 0.0000000000 + x = -3.482463355 + 0.3571428572 x = -3.482463355 + 0.3571428572 Combine like terms: -3.482463355 + 0.3571428572 = -3.1253204978 x = -3.1253204978 Simplifying x = -3.1253204978

Solution

The solution to the problem is based on the solutions from the subproblems. x = {3.8396062122, -3.1253204978}

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