2x^4-21x^2+54=

Solution for 2x^4-21x^2+54= equation:

Simplifying
2x4 + -21x2 + 54 = 0

Reorder the terms:
54 + -21x2 + 2x4 = 0

Solving
54 + -21x2 + 2x4 = 0

Solving for variable 'x'.

Factor a trinomial.
(9 + -2x2)(6 + -1x2) = 0

Subproblem 1
Set the factor '(9 + -2x2)' equal to zero and attempt to solve:

Simplifying
9 + -2x2 = 0

Solving
9 + -2x2 = 0

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

Add '-9' to each side of the equation.
9 + -9 + -2x2 = 0 + -9

Combine like terms: 9 + -9 = 0
0 + -2x2 = 0 + -9
-2x2 = 0 + -9

Combine like terms: 0 + -9 = -9
-2x2 = -9

Divide each side by '-2'.
x2 = 4.5

Simplifying
x2 = 4.5

Take the square root of each side:
x = {-2.121320344, 2.121320344}
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 = {-2.121320344, 2.121320344, -2.449489743, 2.449489743}