Appendix A - Review - A.4 Factoring Polynomials - A.4 Assess Your Understanding - Page A40: 90

$x(x-2)(x+10)$

For the polynomial $x^3 + 8x^2 - 20x=x(x^2 +8x - 20)$ we have to find integers whose product is $-20$ and whose sum is $8$. That is, we have $-2$ and $10$, where $-2+10=8$ and $-2\times (10)=-20$. Thus $$ x(x^2 +8x - 20)=x(x-2)(x+10) .$$