Answer:
[tex](x^2-9)(x^2+9)\\(x-3)(x+3)(x^2+9)[/tex]
Step-by-step explanation:
To factor the expression, factor as a difference of squares. Find the square root of each term and write it in this form (x+a)(x-a).
[tex]x^4 - 81\\(x^2 - 9)(x^2 + 9)[/tex]
Factor x² - 9 as a difference of squares.
[tex](x^2-9)(x^2+9)\\(x-3)(x+3)(x^2+9)[/tex]
This is the most factored form because a sum of squares cannot be factored.
