(5+u)(4u-1)=0

Solution for (5+u)(4u-1)=0 equation:

Simplifying
(5 + u)(4u + -1) = 0

Reorder the terms:
(5 + u)(-1 + 4u) = 0

Multiply (5 + u) * (-1 + 4u)
(5(-1 + 4u) + u(-1 + 4u)) = 0
((-1 * 5 + 4u * 5) + u(-1 + 4u)) = 0
((-5 + 20u) + u(-1 + 4u)) = 0
(-5 + 20u + (-1 * u + 4u * u)) = 0
(-5 + 20u + (-1u + 4u2)) = 0

Combine like terms: 20u + -1u = 19u
(-5 + 19u + 4u2) = 0

Solving
-5 + 19u + 4u2 = 0

Solving for variable 'u'.

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

Subproblem 1
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
Subproblem 2
Set the factor '(1 + -4u)' equal to zero and attempt to solve:

Simplifying
1 + -4u = 0

Solving
1 + -4u = 0

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

Add '-1' to each side of the equation.
1 + -1 + -4u = 0 + -1

Combine like terms: 1 + -1 = 0
0 + -4u = 0 + -1
-4u = 0 + -1

Combine like terms: 0 + -1 = -1
-4u = -1

Divide each side by '-4'.
u = 0.25

Simplifying
u = 0.25
Solution
u = {-5, 0.25}