x(x-8)=3x^2+4

Solution for x(x-8)=3x^2+4 equation:

Simplifying
x(x + -8) = 3x2 + 4

Reorder the terms:
x(-8 + x) = 3x2 + 4
(-8 * x + x * x) = 3x2 + 4
(-8x + x2) = 3x2 + 4

Reorder the terms:
-8x + x2 = 4 + 3x2

Solving
-8x + x2 = 4 + 3x2

Solving for variable 'x'.

Reorder the terms:
-4 + -8x + x2 + -3x2 = 4 + 3x2 + -4 + -3x2

Combine like terms: x2 + -3x2 = -2x2
-4 + -8x + -2x2 = 4 + 3x2 + -4 + -3x2

Reorder the terms:
-4 + -8x + -2x2 = 4 + -4 + 3x2 + -3x2

Combine like terms: 4 + -4 = 0
-4 + -8x + -2x2 = 0 + 3x2 + -3x2
-4 + -8x + -2x2 = 3x2 + -3x2

Combine like terms: 3x2 + -3x2 = 0
-4 + -8x + -2x2 = 0

Factor out the Greatest Common Factor (GCF), '-2'.
-2(2 + 4x + x2) = 0

Ignore the factor -2.
Subproblem 1
Set the factor '(2 + 4x + x2)' equal to zero and attempt to solve:

Simplifying
2 + 4x + x2 = 0

Solving
2 + 4x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-2' to each side of the equation.
2 + 4x + -2 + x2 = 0 + -2

Reorder the terms:
2 + -2 + 4x + x2 = 0 + -2

Combine like terms: 2 + -2 = 0
0 + 4x + x2 = 0 + -2
4x + x2 = 0 + -2

Combine like terms: 0 + -2 = -2
4x + x2 = -2

The x term is 4x.  Take half its coefficient (2).
Square it (4) and add it to both sides.

Add '4' to each side of the equation.
4x + 4 + x2 = -2 + 4

Reorder the terms:
4 + 4x + x2 = -2 + 4

Combine like terms: -2 + 4 = 2
4 + 4x + x2 = 2

Factor a perfect square on the left side:
(x + 2)(x + 2) = 2

Calculate the square root of the right side: 1.414213562

Break this problem into two subproblems by setting 
(x + 2) equal to 1.414213562 and -1.414213562.

Subproblem 1
x + 2 = 1.414213562

Simplifying
x + 2 = 1.414213562

Reorder the terms:
2 + x = 1.414213562

Solving
2 + x = 1.414213562

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '-2' to each side of the equation.
2 + -2 + x = 1.414213562 + -2

Combine like terms: 2 + -2 = 0
0 + x = 1.414213562 + -2
x = 1.414213562 + -2

Combine like terms: 1.414213562 + -2 = -0.585786438
x = -0.585786438

Simplifying
x = -0.585786438

Subproblem 2
x + 2 = -1.414213562

Simplifying
x + 2 = -1.414213562

Reorder the terms:
2 + x = -1.414213562

Solving
2 + x = -1.414213562

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '-2' to each side of the equation.
2 + -2 + x = -1.414213562 + -2

Combine like terms: 2 + -2 = 0
0 + x = -1.414213562 + -2
x = -1.414213562 + -2

Combine like terms: -1.414213562 + -2 = -3.414213562
x = -3.414213562

Simplifying
x = -3.414213562

Solution
The solution to the problem is based on the solutions
from the subproblems.
x = {-0.585786438, -3.414213562}
Solution
x = {-0.585786438, -3.414213562}