X^6-9x^4-x^2+9=0 me i don't understand this

So firstly, I will be factoring by grouping. For this, factor x⁶ - 9x⁴ and -x² + 9 separately. Make sure that they have the same quantity on the inside of the parentheses:

Now, you can rewrite the equation as:

However, it's not completely factored. Next, we will apply the formula for the difference of squares, which is . In this case:

Next, we will apply the difference of squares once more with the second factor as such:

The factored form of this equation is: