(Solved): Use the Second Derivative Test to find the location of all local extrema in the interval \( (-8,2) ...

Use the Second Derivative Test to find the location of all local extrema in the interval \( (-8,2) \) for the function given below. \[ f(x)=\frac{2 x^{3}}{3}+5 x^{2}+12 x \] If there is more than one local maxima or local minima, write each value of \( x \) separated by a comma. If a local maxima or local minima does not occur on the function, enter \( \varnothing \) in the appropriate box. Answer should be exact. Provide your answer below: The local maxima occur at \( x= \) The local minima occur at \( x= \)