90=(4w-9)w

Solution for 90=(4w-9)w equation:

Simplifying
90 = (4w + -9) * w

Reorder the terms:
90 = (-9 + 4w) * w

Reorder the terms for easier multiplication:
90 = w(-9 + 4w)
90 = (-9 * w + 4w * w)
90 = (-9w + 4w2)

Solving
90 = -9w + 4w2

Solving for variable 'w'.

Reorder the terms:
90 + 9w + -4w2 = -9w + 9w + 4w2 + -4w2

Combine like terms: -9w + 9w = 0
90 + 9w + -4w2 = 0 + 4w2 + -4w2
90 + 9w + -4w2 = 4w2 + -4w2

Combine like terms: 4w2 + -4w2 = 0
90 + 9w + -4w2 = 0

Factor a trinomial.
(6 + -1w)(15 + 4w) = 0

Subproblem 1
Set the factor '(6 + -1w)' equal to zero and attempt to solve:

Simplifying
6 + -1w = 0

Solving
6 + -1w = 0

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

Add '-6' to each side of the equation.
6 + -6 + -1w = 0 + -6

Combine like terms: 6 + -6 = 0
0 + -1w = 0 + -6
-1w = 0 + -6

Combine like terms: 0 + -6 = -6
-1w = -6

Divide each side by '-1'.
w = 6

Simplifying
w = 6
Subproblem 2
Set the factor '(15 + 4w)' equal to zero and attempt to solve:

Simplifying
15 + 4w = 0

Solving
15 + 4w = 0

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

Add '-15' to each side of the equation.
15 + -15 + 4w = 0 + -15

Combine like terms: 15 + -15 = 0
0 + 4w = 0 + -15
4w = 0 + -15

Combine like terms: 0 + -15 = -15
4w = -15

Divide each side by '4'.
w = -3.75

Simplifying
w = -3.75
Solution
w = {6, -3.75}