2(x^2-5)(x^2+4)=0

Solution for 2(x^2-5)(x^2+4)=0 equation:

Simplifying
2(x2 + -5)(x2 + 4) = 0

Reorder the terms:
2(-5 + x2)(x2 + 4) = 0

Reorder the terms:
2(-5 + x2)(4 + x2) = 0

Multiply (-5 + x2) * (4 + x2)
2(-5(4 + x2) + x2(4 + x2)) = 0
2((4 * -5 + x2 * -5) + x2(4 + x2)) = 0
2((-20 + -5x2) + x2(4 + x2)) = 0
2(-20 + -5x2 + (4 * x2 + x2 * x2)) = 0
2(-20 + -5x2 + (4x2 + x4)) = 0

Combine like terms: -5x2 + 4x2 = -1x2
2(-20 + -1x2 + x4) = 0
(-20 * 2 + -1x2 * 2 + x4 * 2) = 0
(-40 + -2x2 + 2x4) = 0

Solving
-40 + -2x2 + 2x4 = 0

Solving for variable 'x'.

Factor out the Greatest Common Factor (GCF), '2'.
2(-20 + -1x2 + x4) = 0

Factor a trinomial.
2((-4 + -1x2)(5 + -1x2)) = 0

Ignore the factor 2.
Subproblem 1
Set the factor '(-4 + -1x2)' equal to zero and attempt to solve:

Simplifying
-4 + -1x2 = 0

Solving
-4 + -1x2 = 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 + -1x2 = 0 + 4

Combine like terms: -4 + 4 = 0
0 + -1x2 = 0 + 4
-1x2 = 0 + 4

Combine like terms: 0 + 4 = 4
-1x2 = 4

Divide each side by '-1'.
x2 = -4

Simplifying
x2 = -4

The solution to this equation could not be determined.

This subproblem is being ignored because a solution could not be determined.
Subproblem 2
Set the factor '(5 + -1x2)' equal to zero and attempt to solve:

Simplifying
5 + -1x2 = 0

Solving
5 + -1x2 = 0

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

Add '-5' to each side of the equation.
5 + -5 + -1x2 = 0 + -5

Combine like terms: 5 + -5 = 0
0 + -1x2 = 0 + -5
-1x2 = 0 + -5

Combine like terms: 0 + -5 = -5
-1x2 = -5

Divide each side by '-1'.
x2 = 5

Simplifying
x2 = 5

Take the square root of each side:
x = {-2.236067978, 2.236067978}
Solution
x = {-2.236067978, 2.236067978}