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

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

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

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

Multiply (1 + -1v) * (5 + 4v)
(1(5 + 4v) + -1v * (5 + 4v)) = 0
((5 * 1 + 4v * 1) + -1v * (5 + 4v)) = 0
((5 + 4v) + -1v * (5 + 4v)) = 0
(5 + 4v + (5 * -1v + 4v * -1v)) = 0
(5 + 4v + (-5v + -4v2)) = 0

Combine like terms: 4v + -5v = -1v
(5 + -1v + -4v2) = 0

Solving
5 + -1v + -4v2 = 0

Solving for variable 'v'.

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

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

Simplifying
1 + -1v = 0

Solving
1 + -1v = 0

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

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

Combine like terms: 1 + -1 = 0
0 + -1v = 0 + -1
-1v = 0 + -1

Combine like terms: 0 + -1 = -1
-1v = -1

Divide each side by '-1'.
v = 1

Simplifying
v = 1
Subproblem 2
Set the factor '(5 + 4v)' equal to zero and attempt to solve:

Simplifying
5 + 4v = 0

Solving
5 + 4v = 0

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

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

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

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

Divide each side by '4'.
v = -1.25

Simplifying
v = -1.25
Solution
v = {1, -1.25}