315=(6+x)x

Solution for 315=(6+x)x equation:

Simplifying
315 = (6 + x) * x

Reorder the terms for easier multiplication:
315 = x(6 + x)
315 = (6 * x + x * x)
315 = (6x + x2)

Solving
315 = 6x + x2

Solving for variable 'x'.

Reorder the terms:
315 + -6x + -1x2 = 6x + -6x + x2 + -1x2

Combine like terms: 6x + -6x = 0
315 + -6x + -1x2 = 0 + x2 + -1x2
315 + -6x + -1x2 = x2 + -1x2

Combine like terms: x2 + -1x2 = 0
315 + -6x + -1x2 = 0

Factor a trinomial.
(15 + -1x)(21 + x) = 0

Subproblem 1
Set the factor '(15 + -1x)' equal to zero and attempt to solve:

Simplifying
15 + -1x = 0

Solving
15 + -1x = 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 + -1x = 0 + -15

Combine like terms: 15 + -15 = 0
0 + -1x = 0 + -15
-1x = 0 + -15

Combine like terms: 0 + -15 = -15
-1x = -15

Divide each side by '-1'.
x = 15

Simplifying
x = 15
Subproblem 2
Set the factor '(21 + x)' equal to zero and attempt to solve:

Simplifying
21 + x = 0

Solving
21 + x = 0

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

Add '-21' to each side of the equation.
21 + -21 + x = 0 + -21

Combine like terms: 21 + -21 = 0
0 + x = 0 + -21
x = 0 + -21

Combine like terms: 0 + -21 = -21
x = -21

Simplifying
x = -21
Solution
x = {15, -21}