100x^4+399x^2-4=0

Solution for 100x^4+399x^2-4=0 equation:

Simplifying
100x4 + 399x2 + -4 = 0

Reorder the terms:
-4 + 399x2 + 100x4 = 0

Solving
-4 + 399x2 + 100x4 = 0

Solving for variable 'x'.

Factor a trinomial.
(-4 + -1x2)(1 + -100x2) = 0

Factor a difference between two squares.
(-4 + -1x2)((1 + 10x)(1 + -10x)) = 0

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 '(1 + 10x)' equal to zero and attempt to solve:

Simplifying
1 + 10x = 0

Solving
1 + 10x = 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 + 10x = 0 + -1

Combine like terms: 1 + -1 = 0
0 + 10x = 0 + -1
10x = 0 + -1

Combine like terms: 0 + -1 = -1
10x = -1

Divide each side by '10'.
x = -0.1

Simplifying
x = -0.1
Subproblem 3
Set the factor '(1 + -10x)' equal to zero and attempt to solve:

Simplifying
1 + -10x = 0

Solving
1 + -10x = 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 + -10x = 0 + -1

Combine like terms: 1 + -1 = 0
0 + -10x = 0 + -1
-10x = 0 + -1

Combine like terms: 0 + -1 = -1
-10x = -1

Divide each side by '-10'.
x = 0.1

Simplifying
x = 0.1
Solution
x = {-0.1, 0.1}