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

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

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

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

Multiply (4 + 5u) * (5 + u)
(4(5 + u) + 5u * (5 + u)) = 0
((5 * 4 + u * 4) + 5u * (5 + u)) = 0
((20 + 4u) + 5u * (5 + u)) = 0
(20 + 4u + (5 * 5u + u * 5u)) = 0
(20 + 4u + (25u + 5u2)) = 0

Combine like terms: 4u + 25u = 29u
(20 + 29u + 5u2) = 0

Solving
20 + 29u + 5u2 = 0

Solving for variable 'u'.

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

Subproblem 1
Set the factor '(5 + u)' equal to zero and attempt to solve:

Simplifying
5 + u = 0

Solving
5 + u = 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 + u = 0 + -5

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

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

Simplifying
u = -5
Subproblem 2
Set the factor '(4 + 5u)' equal to zero and attempt to solve:

Simplifying
4 + 5u = 0

Solving
4 + 5u = 0

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

Add '-4' to each side of the equation.
4 + -4 + 5u = 0 + -4

Combine like terms: 4 + -4 = 0
0 + 5u = 0 + -4
5u = 0 + -4

Combine like terms: 0 + -4 = -4
5u = -4

Divide each side by '5'.
u = -0.8

Simplifying
u = -0.8
Solution
u = {-5, -0.8}