Answer
$x^3-5x^2-6x+30$
Work Step by Step
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}
