Answer
$8$
Work Step by Step
Using $C(n,r)=\dfrac{n!}{r!(n-r)!},$ the given expression, $C(
8,1
)$ evaluates to
\begin{array}{l}\require{cancel}
=\dfrac{8!}{1!(8-1)!}
\\\\=
\dfrac{8!}{1!7!}
\\\\=
\dfrac{8(7!)}{1(7!)}
\\\\=
\dfrac{8(\cancel{7!})}{1(\cancel{7!})}
\\\\=
8
\end{array}
