(u-9)(u-3)=0

Solution for (u-9)(u-3)=0 equation:

Simplifying
(u + -9)(u + -3) = 0

Reorder the terms:
(-9 + u)(u + -3) = 0

Reorder the terms:
(-9 + u)(-3 + u) = 0

Multiply (-9 + u) * (-3 + u)
(-9(-3 + u) + u(-3 + u)) = 0
((-3 * -9 + u * -9) + u(-3 + u)) = 0
((27 + -9u) + u(-3 + u)) = 0
(27 + -9u + (-3 * u + u * u)) = 0
(27 + -9u + (-3u + u2)) = 0

Combine like terms: -9u + -3u = -12u
(27 + -12u + u2) = 0

Solving
27 + -12u + u2 = 0

Solving for variable 'u'.

Factor a trinomial.
(3 + -1u)(9 + -1u) = 0

Subproblem 1
Set the factor '(3 + -1u)' equal to zero and attempt to solve:

Simplifying
3 + -1u = 0

Solving
3 + -1u = 0

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

Add '-3' to each side of the equation.
3 + -3 + -1u = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -1u = 0 + -3
-1u = 0 + -3

Combine like terms: 0 + -3 = -3
-1u = -3

Divide each side by '-1'.
u = 3

Simplifying
u = 3
Subproblem 2
Set the factor '(9 + -1u)' equal to zero and attempt to solve:

Simplifying
9 + -1u = 0

Solving
9 + -1u = 0

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

Add '-9' to each side of the equation.
9 + -9 + -1u = 0 + -9

Combine like terms: 9 + -9 = 0
0 + -1u = 0 + -9
-1u = 0 + -9

Combine like terms: 0 + -9 = -9
-1u = -9

Divide each side by '-1'.
u = 9

Simplifying
u = 9
Solution
u = {3, 9}