Move to the left side of the equation by adding it to both sides.

Rewrite as .

Let . Substitute for all occurrences of .

Rewrite as .

Check the middle term by multiplying and compare this result with the middle term in the original expression.

Simplify.

Factor using the perfect square trinomial rule , where and .

Replace all occurrences of with .

Rewrite as .

Since both terms are perfect squares, factor using the difference of squares formula, where and .

Apply the product rule to .

If any individual factor on the left side of the equation is equal to , the entire expression will be equal to .

Set the first factor equal to .

Set the equal to .

Subtract from both sides of the equation.

Set the next factor equal to .

Set the equal to .

Add to both sides of the equation.

The final solution is all the values that make true.

Solve by Factoring x^4-8x^2=-16