Question

Factor Completely: x^4 - 81

Answer 1

(x-3)(x+3) (x^2+9)

Explanation:

Factor

x^4 - 81

This is the difference of squares

(x^2 - 9) (x^2 +9)

Now the first term is the difference of squares

(x-3)(x+3) (x^2+9)