Answer
$(b)\;x=1$ and $(d)\;x=-1$.
Work Step by Step
The given expression is
$=\frac{x^3}{x^2-1} $
(a) Substitute $x=3$.
$=\frac{3^3}{3^2-1} $
Simplify.
$=\frac{27}{9-1} $
$=\frac{27}{8} $
(b) Substitute $x=1$.
$=\frac{1^3}{1^2-1} $
Simplify.
$=\frac{1}{1-1} $
$=\frac{1}{0} $
Not defined.
(c) Substitute $x=0$.
$=\frac{0^3}{0^2-1} $
Simplify.
$=\frac{0}{0-1} $
$=\frac{0}{-1} $
$=0 $
(d) Substitute $x=-1$.
$=\frac{(-1)^3}{(-1)^2-1} $
Simplify.
$=\frac{-1}{1-1} $
$=\frac{-1}{0} $
Not defined.
Hence, the correct answers are $(b)\;x=1$ and $(d)\;x=-1$.
