Question

Draw the graphs of the polynomial $f\left(x\right)=x^3-4x$

Answer 1

$x$	$-2$	$-1$	$0$	$1$	$2$
$y$	$0$	$3$	$0$	$-3$	$0$

$f\left(x\right)=x^3-4x$

$y=x^3-4x$

For $x=0$

$y=x^3-4x$

$=0^3-4\times 0$

$=0$

For $x=1$

$y=1^3-4\times 1$

$=1-4$

$=-3$

For $x=-1$

$y=(-1{)}^3-4\times -1$

$=-1+4$

$=3$

For $x=2$

$y=2^3-4\times 2$

$=8-4\times 2$

$=8-8$

$=0$

For $x=-2$

$y=(-2{)}^3-4\times 2$

$=-8+8=0$