Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$x^3-5x^2-6x+30$
Using $(a+b)(c+d)=ac+ad+bc+bd$ or the product of $2$ binomials, the given expression, $(x-5)(x^2-6)$, is equivalent to \begin{array}{l}\require{cancel} x(x^2)+x(-6)-5(x^2)-5(-6) \\\\= x^3-6x-5x^2+30 \\\\= x^3-5x^2-6x+30 .\end{array}