(w+18)(w-21)=0

Solution for (w+18)(w-21)=0 equation:

Simplifying
(w + 18)(w + -21) = 0

Reorder the terms:
(18 + w)(w + -21) = 0

Reorder the terms:
(18 + w)(-21 + w) = 0

Multiply (18 + w) * (-21 + w)
(18(-21 + w) + w(-21 + w)) = 0
((-21 * 18 + w * 18) + w(-21 + w)) = 0
((-378 + 18w) + w(-21 + w)) = 0
(-378 + 18w + (-21 * w + w * w)) = 0
(-378 + 18w + (-21w + w2)) = 0

Combine like terms: 18w + -21w = -3w
(-378 + -3w + w2) = 0

Solving
-378 + -3w + w2 = 0

Solving for variable 'w'.

Factor a trinomial.
(-18 + -1w)(21 + -1w) = 0

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

Simplifying
-18 + -1w = 0

Solving
-18 + -1w = 0

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

Add '18' to each side of the equation.
-18 + 18 + -1w = 0 + 18

Combine like terms: -18 + 18 = 0
0 + -1w = 0 + 18
-1w = 0 + 18

Combine like terms: 0 + 18 = 18
-1w = 18

Divide each side by '-1'.
w = -18

Simplifying
w = -18
Subproblem 2
Set the factor '(21 + -1w)' equal to zero and attempt to solve:

Simplifying
21 + -1w = 0

Solving
21 + -1w = 0

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

Add '-21' to each side of the equation.
21 + -21 + -1w = 0 + -21

Combine like terms: 21 + -21 = 0
0 + -1w = 0 + -21
-1w = 0 + -21

Combine like terms: 0 + -21 = -21
-1w = -21

Divide each side by '-1'.
w = 21

Simplifying
w = 21
Solution
w = {-18, 21}