(k+3)(3k+7)=0

Solution for (k+3)(3k+7)=0 equation:

Simplifying
(k + 3)(3k + 7) = 0

Reorder the terms:
(3 + k)(3k + 7) = 0

Reorder the terms:
(3 + k)(7 + 3k) = 0

Multiply (3 + k) * (7 + 3k)
(3(7 + 3k) + k(7 + 3k)) = 0
((7 * 3 + 3k * 3) + k(7 + 3k)) = 0
((21 + 9k) + k(7 + 3k)) = 0
(21 + 9k + (7 * k + 3k * k)) = 0
(21 + 9k + (7k + 3k2)) = 0

Combine like terms: 9k + 7k = 16k
(21 + 16k + 3k2) = 0

Solving
21 + 16k + 3k2 = 0

Solving for variable 'k'.

Factor a trinomial.
(3 + k)(7 + 3k) = 0

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

Simplifying
3 + k = 0

Solving
3 + k = 0

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

Add '-3' to each side of the equation.
3 + -3 + k = 0 + -3

Combine like terms: 3 + -3 = 0
0 + k = 0 + -3
k = 0 + -3

Combine like terms: 0 + -3 = -3
k = -3

Simplifying
k = -3
Subproblem 2
Set the factor '(7 + 3k)' equal to zero and attempt to solve:

Simplifying
7 + 3k = 0

Solving
7 + 3k = 0

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

Add '-7' to each side of the equation.
7 + -7 + 3k = 0 + -7

Combine like terms: 7 + -7 = 0
0 + 3k = 0 + -7
3k = 0 + -7

Combine like terms: 0 + -7 = -7
3k = -7

Divide each side by '3'.
k = -2.333333333

Simplifying
k = -2.333333333
Solution
k = {-3, -2.333333333}