105=x(x+8)

Solution for 105=x(x+8) equation:

Simplifying
105 = x(x + 8)

Reorder the terms:
105 = x(8 + x)
105 = (8 * x + x * x)
105 = (8x + x2)

Solving
105 = 8x + x2

Solving for variable 'x'.

Reorder the terms:
105 + -8x + -1x2 = 8x + -8x + x2 + -1x2

Combine like terms: 8x + -8x = 0
105 + -8x + -1x2 = 0 + x2 + -1x2
105 + -8x + -1x2 = x2 + -1x2

Combine like terms: x2 + -1x2 = 0
105 + -8x + -1x2 = 0

Factor a trinomial.
(7 + -1x)(15 + x) = 0

Subproblem 1
Set the factor '(7 + -1x)' equal to zero and attempt to solve:

Simplifying
7 + -1x = 0

Solving
7 + -1x = 0

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

Add '-7' to each side of the equation.
7 + -7 + -1x = 0 + -7

Combine like terms: 7 + -7 = 0
0 + -1x = 0 + -7
-1x = 0 + -7

Combine like terms: 0 + -7 = -7
-1x = -7

Divide each side by '-1'.
x = 7

Simplifying
x = 7
Subproblem 2
Set the factor '(15 + x)' equal to zero and attempt to solve:

Simplifying
15 + x = 0

Solving
15 + x = 0

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

Add '-15' to each side of the equation.
15 + -15 + x = 0 + -15

Combine like terms: 15 + -15 = 0
0 + x = 0 + -15
x = 0 + -15

Combine like terms: 0 + -15 = -15
x = -15

Simplifying
x = -15
Solution
x = {7, -15}