(x^2-16)(x^2+1)=0

Solution for (x^2-16)(x^2+1)=0 equation:

Simplifying
(x2 + -16)(x2 + 1) = 0

Reorder the terms:
(-16 + x2)(x2 + 1) = 0

Reorder the terms:
(-16 + x2)(1 + x2) = 0

Multiply (-16 + x2) * (1 + x2)
(-16(1 + x2) + x2(1 + x2)) = 0
((1 * -16 + x2 * -16) + x2(1 + x2)) = 0
((-16 + -16x2) + x2(1 + x2)) = 0
(-16 + -16x2 + (1 * x2 + x2 * x2)) = 0
(-16 + -16x2 + (1x2 + x4)) = 0

Combine like terms: -16x2 + 1x2 = -15x2
(-16 + -15x2 + x4) = 0

Solving
-16 + -15x2 + x4 = 0

Solving for variable 'x'.

Factor a trinomial.
(-1 + -1x2)(16 + -1x2) = 0

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

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

Simplifying
-1 + -1x2 = 0

Solving
-1 + -1x2 = 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 + -1x2 = 0 + 1

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

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

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

Simplifying
x2 = -1

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

Simplifying
4 + x = 0

Solving
4 + x = 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 + x = 0 + -4

Combine like terms: 4 + -4 = 0
0 + x = 0 + -4
x = 0 + -4

Combine like terms: 0 + -4 = -4
x = -4

Simplifying
x = -4
Subproblem 3
Set the factor '(4 + -1x)' equal to zero and attempt to solve:

Simplifying
4 + -1x = 0

Solving
4 + -1x = 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 + -1x = 0 + -4

Combine like terms: 4 + -4 = 0
0 + -1x = 0 + -4
-1x = 0 + -4

Combine like terms: 0 + -4 = -4
-1x = -4

Divide each side by '-1'.
x = 4

Simplifying
x = 4
Solution
x = {-4, 4}