A biquadratic equation is a quadratic function of a square, having the form f(x)= ax^4+ bx^2 + c. To solve you simply have to rewrite the equation as a quadratic equation: substitute x^4 with u^2 and x^2 with u, to get au^2+ bu + c. See previous post on solving quadratic functions

here.

Don’t forget to substitute back and solve for x. You should get up to 4 solutions; it is a quartic equation after all.

Let’s see how it works (

click here):

Here’s another example (

click here):

Cheers,

Michal