40=4(x+8)10x

Solution for 40=4(x+8)10x equation:

Simplifying
40 = 4(x + 8) * 10x

Reorder the terms:
40 = 4(8 + x) * 10x

Reorder the terms for easier multiplication:
40 = 4 * 10x(8 + x)

Multiply 4 * 10
40 = 40x(8 + x)
40 = (8 * 40x + x * 40x)
40 = (320x + 40x2)

Solving
40 = 320x + 40x2

Solving for variable 'x'.

Reorder the terms:
40 + -320x + -40x2 = 320x + -320x + 40x2 + -40x2

Combine like terms: 320x + -320x = 0
40 + -320x + -40x2 = 0 + 40x2 + -40x2
40 + -320x + -40x2 = 40x2 + -40x2

Combine like terms: 40x2 + -40x2 = 0
40 + -320x + -40x2 = 0

Factor out the Greatest Common Factor (GCF), '40'.
40(1 + -8x + -1x2) = 0

Ignore the factor 40.
Subproblem 1
Set the factor '(1 + -8x + -1x2)' equal to zero and attempt to solve:

Simplifying
1 + -8x + -1x2 = 0

Solving
1 + -8x + -1x2 = 0

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

Divide each side by '-1'.
-1 + 8x + x2 = 0

Move the constant term to the right:

Add '1' to each side of the equation.
-1 + 8x + 1 + x2 = 0 + 1

Reorder the terms:
-1 + 1 + 8x + x2 = 0 + 1

Combine like terms: -1 + 1 = 0
0 + 8x + x2 = 0 + 1
8x + x2 = 0 + 1

Combine like terms: 0 + 1 = 1
8x + x2 = 1

The x term is 8x.  Take half its coefficient (4).
Square it (16) and add it to both sides.

Add '16' to each side of the equation.
8x + 16 + x2 = 1 + 16

Reorder the terms:
16 + 8x + x2 = 1 + 16

Combine like terms: 1 + 16 = 17
16 + 8x + x2 = 17

Factor a perfect square on the left side:
(x + 4)(x + 4) = 17

Calculate the square root of the right side: 4.123105626

Break this problem into two subproblems by setting 
(x + 4) equal to 4.123105626 and -4.123105626.

Subproblem 1
x + 4 = 4.123105626

Simplifying
x + 4 = 4.123105626

Reorder the terms:
4 + x = 4.123105626

Solving
4 + x = 4.123105626

Solving for variable 'x'.

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

Add '-4' to each side of the equation.
4 + -4 + x = 4.123105626 + -4

Combine like terms: 4 + -4 = 0
0 + x = 4.123105626 + -4
x = 4.123105626 + -4

Combine like terms: 4.123105626 + -4 = 0.123105626
x = 0.123105626

Simplifying
x = 0.123105626

Subproblem 2
x + 4 = -4.123105626

Simplifying
x + 4 = -4.123105626

Reorder the terms:
4 + x = -4.123105626

Solving
4 + x = -4.123105626

Solving for variable 'x'.

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

Add '-4' to each side of the equation.
4 + -4 + x = -4.123105626 + -4

Combine like terms: 4 + -4 = 0
0 + x = -4.123105626 + -4
x = -4.123105626 + -4

Combine like terms: -4.123105626 + -4 = -8.123105626
x = -8.123105626

Simplifying
x = -8.123105626

Solution
The solution to the problem is based on the solutions
from the subproblems.
x = {0.123105626, -8.123105626}
Solution
x = {0.123105626, -8.123105626}