## College Algebra 7th Edition

$(x^{2}+2)(x+1)(x-1)$
We treat $x^4$ as $(x^2)^2$. Then we use $a^2-b^2=(a+b)(a-b)$: $x^{4}+x^{2}-2=(x^{2})^{2}+x^{2}-2=(x^{2}+2)(x^{2}-1)=(x^{2}+2)(x+1)(x-1)$