136=(2x+4)(x+4)

Solution for 136=(2x+4)(x+4) equation:

Simplifying
136 = (2x + 4)(x + 4)

Reorder the terms:
136 = (4 + 2x)(x + 4)

Reorder the terms:
136 = (4 + 2x)(4 + x)

Multiply (4 + 2x) * (4 + x)
136 = (4(4 + x) + 2x * (4 + x))
136 = ((4 * 4 + x * 4) + 2x * (4 + x))
136 = ((16 + 4x) + 2x * (4 + x))
136 = (16 + 4x + (4 * 2x + x * 2x))
136 = (16 + 4x + (8x + 2x2))

Combine like terms: 4x + 8x = 12x
136 = (16 + 12x + 2x2)

Solving
136 = 16 + 12x + 2x2

Solving for variable 'x'.

Combine like terms: 136 + -16 = 120
120 + -12x + -2x2 = 16 + 12x + 2x2 + -16 + -12x + -2x2

Reorder the terms:
120 + -12x + -2x2 = 16 + -16 + 12x + -12x + 2x2 + -2x2

Combine like terms: 16 + -16 = 0
120 + -12x + -2x2 = 0 + 12x + -12x + 2x2 + -2x2
120 + -12x + -2x2 = 12x + -12x + 2x2 + -2x2

Combine like terms: 12x + -12x = 0
120 + -12x + -2x2 = 0 + 2x2 + -2x2
120 + -12x + -2x2 = 2x2 + -2x2

Combine like terms: 2x2 + -2x2 = 0
120 + -12x + -2x2 = 0

Factor out the Greatest Common Factor (GCF), '2'.
2(60 + -6x + -1x2) = 0

Ignore the factor 2.
Subproblem 1
Set the factor '(60 + -6x + -1x2)' equal to zero and attempt to solve:

Simplifying
60 + -6x + -1x2 = 0

Solving
60 + -6x + -1x2 = 0

Begin completing the square.  Divide all terms by
-1 the coefficient of the squared term: 

Divide each side by '-1'.
-60 + 6x + x2 = 0

Move the constant term to the right:

Add '60' to each side of the equation.
-60 + 6x + 60 + x2 = 0 + 60

Reorder the terms:
-60 + 60 + 6x + x2 = 0 + 60

Combine like terms: -60 + 60 = 0
0 + 6x + x2 = 0 + 60
6x + x2 = 0 + 60

Combine like terms: 0 + 60 = 60
6x + x2 = 60

The x term is 6x.  Take half its coefficient (3).
Square it (9) and add it to both sides.

Add '9' to each side of the equation.
6x + 9 + x2 = 60 + 9

Reorder the terms:
9 + 6x + x2 = 60 + 9

Combine like terms: 60 + 9 = 69
9 + 6x + x2 = 69

Factor a perfect square on the left side:
(x + 3)(x + 3) = 69

Calculate the square root of the right side: 8.306623863

Break this problem into two subproblems by setting 
(x + 3) equal to 8.306623863 and -8.306623863.

Subproblem 1
x + 3 = 8.306623863

Simplifying
x + 3 = 8.306623863

Reorder the terms:
3 + x = 8.306623863

Solving
3 + x = 8.306623863

Solving for variable 'x'.

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

Add '-3' to each side of the equation.
3 + -3 + x = 8.306623863 + -3

Combine like terms: 3 + -3 = 0
0 + x = 8.306623863 + -3
x = 8.306623863 + -3

Combine like terms: 8.306623863 + -3 = 5.306623863
x = 5.306623863

Simplifying
x = 5.306623863

Subproblem 2
x + 3 = -8.306623863

Simplifying
x + 3 = -8.306623863

Reorder the terms:
3 + x = -8.306623863

Solving
3 + x = -8.306623863

Solving for variable 'x'.

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

Add '-3' to each side of the equation.
3 + -3 + x = -8.306623863 + -3

Combine like terms: 3 + -3 = 0
0 + x = -8.306623863 + -3
x = -8.306623863 + -3

Combine like terms: -8.306623863 + -3 = -11.306623863
x = -11.306623863

Simplifying
x = -11.306623863

Solution
The solution to the problem is based on the solutions
from the subproblems.
x = {5.306623863, -11.306623863}
Solution
x = {5.306623863, -11.306623863}