Question

#7
$x^4 - 16$

Explanation:

Step1: Recognize difference of squares

$x^4 - 16 = (x^2)^2 - 4^2$

Step2: Apply difference of squares formula

$(x^2 - 4)(x^2 + 4)$

Step3: Factor remaining difference of squares

$(x - 2)(x + 2)(x^2 + 4)$

Answer:

$(x - 2)(x + 2)(x^2 + 4)$