(x+4)(2x+1)=0

Solution for (x+4)(2x+1)=0 equation:

Simplifying
(x + 4)(2x + 1) = 0

Reorder the terms:
(4 + x)(2x + 1) = 0

Reorder the terms:
(4 + x)(1 + 2x) = 0

Multiply (4 + x) * (1 + 2x)
(4(1 + 2x) + x(1 + 2x)) = 0
((1 * 4 + 2x * 4) + x(1 + 2x)) = 0
((4 + 8x) + x(1 + 2x)) = 0
(4 + 8x + (1 * x + 2x * x)) = 0
(4 + 8x + (1x + 2x2)) = 0

Combine like terms: 8x + 1x = 9x
(4 + 9x + 2x2) = 0

Solving
4 + 9x + 2x2 = 0

Solving for variable 'x'.

Factor a trinomial.
(4 + x)(1 + 2x) = 0

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

Simplifying
4 + x = 0

Solving
4 + x = 0

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

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

Combine like terms: 4 + -4 = 0
0 + x = 0 + -4
x = 0 + -4

Combine like terms: 0 + -4 = -4
x = -4

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

Simplifying
1 + 2x = 0

Solving
1 + 2x = 0

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

Add '-1' to each side of the equation.
1 + -1 + 2x = 0 + -1

Combine like terms: 1 + -1 = 0
0 + 2x = 0 + -1
2x = 0 + -1

Combine like terms: 0 + -1 = -1
2x = -1

Divide each side by '2'.
x = -0.5

Simplifying
x = -0.5
Solution
x = {-4, -0.5}