## Elementary Algebra

$(x-1)(x+1)(x^2+1)$
The given expression can be written as $=(x^2)^2-1^2$ The binomial above is a difference of two squares. RECALL: $a^2-b^2=(a-b)(a+b)$ Factor the difference of two squares using the formula above with $a=x^2$ and $b=1$ to obtain: $=(x^2-1)(x^2+1)$ Factor the first binomial (a difference of two squares) using the formula above with $a=x$ and $b=1$ to obtain: $=(x-1)(x+1)(x^2+1)$