(x^4)+(x^2)-42=0

Solution for (x^4)+(x^2)-42=0 equation:

Simplifying
(x4) + (x2) + -42 = 0
x4 + (x2) + -42 = 0
x4 + x2 + -42 = 0

Reorder the terms:
-42 + x2 + x4 = 0

Solving
-42 + x2 + x4 = 0

Solving for variable 'x'.

Factor a trinomial.
(-7 + -1x2)(6 + -1x2) = 0

Subproblem 1
Set the factor '(-7 + -1x2)' equal to zero and attempt to solve:

Simplifying
-7 + -1x2 = 0

Solving
-7 + -1x2 = 0

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

Add '7' to each side of the equation.
-7 + 7 + -1x2 = 0 + 7

Combine like terms: -7 + 7 = 0
0 + -1x2 = 0 + 7
-1x2 = 0 + 7

Combine like terms: 0 + 7 = 7
-1x2 = 7

Divide each side by '-1'.
x2 = -7

Simplifying
x2 = -7

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 '(6 + -1x2)' equal to zero and attempt to solve:

Simplifying
6 + -1x2 = 0

Solving
6 + -1x2 = 0

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

Add '-6' to each side of the equation.
6 + -6 + -1x2 = 0 + -6

Combine like terms: 6 + -6 = 0
0 + -1x2 = 0 + -6
-1x2 = 0 + -6

Combine like terms: 0 + -6 = -6
-1x2 = -6

Divide each side by '-1'.
x2 = 6

Simplifying
x2 = 6

Take the square root of each side:
x = {-2.449489743, 2.449489743}
Solution
x = {-2.449489743, 2.449489743}