7x^2+8x+-84=

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Solution for 7x^2+8x+-84= equation:


Simplifying
7x2 + 8x + -84 = 0

Reorder the terms:
-84 + 8x + 7x2 = 0

Solving
-84 + 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'.
-12 + 1.142857143x + x2 = 0

Move the constant term to the right:

Add '12' to each side of the equation.
-12 + 1.142857143x + 12 + x2 = 0 + 12

Reorder the terms:
-12 + 12 + 1.142857143x + x2 = 0 + 12

Combine like terms: -12 + 12 = 0
0 + 1.142857143x + x2 = 0 + 12
1.142857143x + x2 = 0 + 12

Combine like terms: 0 + 12 = 12
1.142857143x + x2 = 12

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 = 12 + 0.3265306123

Reorder the terms:
0.3265306123 + 1.142857143x + x2 = 12 + 0.3265306123

Combine like terms: 12 + 0.3265306123 = 12.3265306123
0.3265306123 + 1.142857143x + x2 = 12.3265306123

Factor a perfect square on the left side:
(x + 0.5714285715)(x + 0.5714285715) = 12.3265306123

Calculate the square root of the right side: 3.510915922

Break this problem into two subproblems by setting 
(x + 0.5714285715) equal to 3.510915922 and -3.510915922.

Subproblem 1

x + 0.5714285715 = 3.510915922 Simplifying x + 0.5714285715 = 3.510915922 Reorder the terms: 0.5714285715 + x = 3.510915922 Solving 0.5714285715 + x = 3.510915922 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 = 3.510915922 + -0.5714285715 Combine like terms: 0.5714285715 + -0.5714285715 = 0.0000000000 0.0000000000 + x = 3.510915922 + -0.5714285715 x = 3.510915922 + -0.5714285715 Combine like terms: 3.510915922 + -0.5714285715 = 2.9394873505 x = 2.9394873505 Simplifying x = 2.9394873505

Subproblem 2

x + 0.5714285715 = -3.510915922 Simplifying x + 0.5714285715 = -3.510915922 Reorder the terms: 0.5714285715 + x = -3.510915922 Solving 0.5714285715 + x = -3.510915922 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 = -3.510915922 + -0.5714285715 Combine like terms: 0.5714285715 + -0.5714285715 = 0.0000000000 0.0000000000 + x = -3.510915922 + -0.5714285715 x = -3.510915922 + -0.5714285715 Combine like terms: -3.510915922 + -0.5714285715 = -4.0823444935 x = -4.0823444935 Simplifying x = -4.0823444935

Solution

The solution to the problem is based on the solutions from the subproblems. x = {2.9394873505, -4.0823444935}

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