Consider the function f(x)=3x35x\displaystyle {f{{\left({x}\right)}}}={3}{x}^{{3}}-{5}{x} on the closed interval [2,4]\displaystyle {\left[{2},{4}\right]}.

Find the exact value of the slope of the secant line connecting (2,f(2))\displaystyle {\left({2},{f{{\left({2}\right)}}}\right)} and (4,f(4))\displaystyle {\left({4},{f{{\left({4}\right)}}}\right)}.

m=\displaystyle {m}=  

By the Mean Value Theorem, there exists c\displaystyle {c} in (2,4)\displaystyle {\left({2},{4}\right)} so that m=f(c)\displaystyle {m}={f}'{\left({c}\right)}. Find all values of such c\displaystyle {c} in (2,4)\displaystyle {\left({2},{4}\right)}. Enter exact values. If there is more than one solution, separate them by a comma.

c=\displaystyle {c}=