ea of a critical value?

values are $y-$values where relative extrema may occur.

values are the $y-$values of relative extrema.

values are $x-$values where relative extrema occur.

alues are $x-$values where relative extrema may occur.

re critical values?

because a corner exists at these x$-$values.

$x_5,x_6,x_7,x_8,$ and $x_{10}$ because the slopes of the tangent lines at these points are $0$ or do not $x_6,x_8,$ and $x_{10}$ because relative extrema occur at these points.

they all occur at relative extrema or where the slopes of the tar