x^4-99x^2+288=0

Solution for x^4-99x^2+288=0 equation:

Simplifying
x4 + -99x2 + 288 = 0

Reorder the terms:
288 + -99x2 + x4 = 0

Solving
288 + -99x2 + x4 = 0

Solving for variable 'x'.

Factor a trinomial.
(3 + -1x2)(96 + -1x2) = 0

Subproblem 1
Set the factor '(3 + -1x2)' equal to zero and attempt to solve:

Simplifying
3 + -1x2 = 0

Solving
3 + -1x2 = 0

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

Add '-3' to each side of the equation.
3 + -3 + -1x2 = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -1x2 = 0 + -3
-1x2 = 0 + -3

Combine like terms: 0 + -3 = -3
-1x2 = -3

Divide each side by '-1'.
x2 = 3

Simplifying
x2 = 3

Take the square root of each side:
x = {-1.732050808, 1.732050808}
Subproblem 2
Set the factor '(96 + -1x2)' equal to zero and attempt to solve:

Simplifying
96 + -1x2 = 0

Solving
96 + -1x2 = 0

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

Add '-96' to each side of the equation.
96 + -96 + -1x2 = 0 + -96

Combine like terms: 96 + -96 = 0
0 + -1x2 = 0 + -96
-1x2 = 0 + -96

Combine like terms: 0 + -96 = -96
-1x2 = -96

Divide each side by '-1'.
x2 = 96

Simplifying
x2 = 96

Take the square root of each side:
x = {-9.797958971, 9.797958971}
Solution
x = {-1.732050808, 1.732050808, -9.797958971, 9.797958971}