15=-4u^2+23u

Solution for 15=-4u^2+23u equation:

Simplifying
15 = -4u2 + 23u

Reorder the terms:
15 = 23u + -4u2

Solving
15 = 23u + -4u2

Solving for variable 'u'.

Reorder the terms:
15 + -23u + 4u2 = 23u + -23u + -4u2 + 4u2

Combine like terms: 23u + -23u = 0
15 + -23u + 4u2 = 0 + -4u2 + 4u2
15 + -23u + 4u2 = -4u2 + 4u2

Combine like terms: -4u2 + 4u2 = 0
15 + -23u + 4u2 = 0

Factor a trinomial.
(3 + -4u)(5 + -1u) = 0

Subproblem 1
Set the factor '(3 + -4u)' equal to zero and attempt to solve:

Simplifying
3 + -4u = 0

Solving
3 + -4u = 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 + -4u = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -4u = 0 + -3
-4u = 0 + -3

Combine like terms: 0 + -3 = -3
-4u = -3

Divide each side by '-4'.
u = 0.75

Simplifying
u = 0.75
Subproblem 2
Set the factor '(5 + -1u)' equal to zero and attempt to solve:

Simplifying
5 + -1u = 0

Solving
5 + -1u = 0

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

Add '-5' to each side of the equation.
5 + -5 + -1u = 0 + -5

Combine like terms: 5 + -5 = 0
0 + -1u = 0 + -5
-1u = 0 + -5

Combine like terms: 0 + -5 = -5
-1u = -5

Divide each side by '-1'.
u = 5

Simplifying
u = 5
Solution
u = {0.75, 5}