(x+3)(x+18)=0

Solution for (x+3)(x+18)=0 equation:

Simplifying
(x + 3)(x + 18) = 0

Reorder the terms:
(3 + x)(x + 18) = 0

Reorder the terms:
(3 + x)(18 + x) = 0

Multiply (3 + x) * (18 + x)
(3(18 + x) + x(18 + x)) = 0
((18 * 3 + x * 3) + x(18 + x)) = 0
((54 + 3x) + x(18 + x)) = 0
(54 + 3x + (18 * x + x * x)) = 0
(54 + 3x + (18x + x2)) = 0

Combine like terms: 3x + 18x = 21x
(54 + 21x + x2) = 0

Solving
54 + 21x + x2 = 0

Solving for variable 'x'.

Factor a trinomial.
(18 + x)(3 + x) = 0

Subproblem 1
Set the factor '(18 + x)' equal to zero and attempt to solve:

Simplifying
18 + x = 0

Solving
18 + x = 0

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

Add '-18' to each side of the equation.
18 + -18 + x = 0 + -18

Combine like terms: 18 + -18 = 0
0 + x = 0 + -18
x = 0 + -18

Combine like terms: 0 + -18 = -18
x = -18

Simplifying
x = -18
Subproblem 2
Set the factor '(3 + x)' equal to zero and attempt to solve:

Simplifying
3 + x = 0

Solving
3 + x = 0

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 = 0 + -3

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

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

Simplifying
x = -3
Solution
x = {-18, -3}