(k+4)(5k-1)=

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

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

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

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

Multiply (4 + k) * (-1 + 5k)
(4(-1 + 5k) + k(-1 + 5k)) = 0
((-1 * 4 + 5k * 4) + k(-1 + 5k)) = 0
((-4 + 20k) + k(-1 + 5k)) = 0
(-4 + 20k + (-1 * k + 5k * k)) = 0
(-4 + 20k + (-1k + 5k2)) = 0

Combine like terms: 20k + -1k = 19k
(-4 + 19k + 5k2) = 0

Solving
-4 + 19k + 5k2 = 0

Solving for variable 'k'.

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

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

Simplifying
-4 + -1k = 0

Solving
-4 + -1k = 0

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

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

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

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

Divide each side by '-1'.
k = -4

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

Simplifying
1 + -5k = 0

Solving
1 + -5k = 0

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

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

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

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

Divide each side by '-5'.
k = 0.2

Simplifying
k = 0.2
Solution
k = {-4, 0.2}