x^4-20x^2=125

Solution for x^4-20x^2=125 equation:

Simplifying
x4 + -20x2 = 125

Reorder the terms:
-20x2 + x4 = 125

Solving
-20x2 + x4 = 125

Solving for variable 'x'.

Reorder the terms:
-125 + -20x2 + x4 = 125 + -125

Combine like terms: 125 + -125 = 0
-125 + -20x2 + x4 = 0

Factor a trinomial.
(-5 + -1x2)(25 + -1x2) = 0

Factor a difference between two squares.
(-5 + -1x2)((5 + x)(5 + -1x)) = 0

Subproblem 1
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

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 + x)' equal to zero and attempt to solve:

Simplifying
5 + x = 0

Solving
5 + x = 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 + x = 0 + -5

Combine like terms: 5 + -5 = 0
0 + x = 0 + -5
x = 0 + -5

Combine like terms: 0 + -5 = -5
x = -5

Simplifying
x = -5
Subproblem 3
Set the factor '(5 + -1x)' equal to zero and attempt to solve:

Simplifying
5 + -1x = 0

Solving
5 + -1x = 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 + -1x = 0 + -5

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

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

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

Simplifying
x = 5
Solution
x = {-5, 5}