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Find the locations and types of all relative extrema for the function,

$$f( x ) ={ 2x }^{ 3 }+{ 4x }^{ 2 }-8x-11$$

$f(x)$ has a relative maximum at $x=-\cfrac{1}{2}$.

$f(x)$ has a relative minimum at $x=\cfrac{2}{3}$.

$f(x)$ has a relative maximum at $-\cfrac{2}{3}$ and a relative minimum at $x=4$..

$f(x)$ has a relative maximum at $x=-2$ and a relative minimum at $x=\cfrac{2}{3}$.