Find all solutions to x^4-8x^2+17=0

[Tracker]

How do I go about finding all the solutions to [math]x^4-8x^2+17=0[/math]?

[timo]

By realizing that it is a quadratic equation in x² that you probably know how to find all solutions for.

[hermanntrude]

there are some other methods for solving polynomials. There's an iterative method which works quite nicely... i just wish i could remember how to use it...

[Severian]

You don't need an iterative method for this one - it can be solved exactly in a couple of lines of algebra.