Suppose f(x)\displaystyle {f}'{\left({x}\right)} is continuous for all x\displaystyle {x}, and f(x)\displaystyle {f{{\left({x}\right)}}} has a local extreme value x=7\displaystyle {x}={7}.

Complete the following table with appropriate possibilities for the values of f(x)\displaystyle {f}'{\left({x}\right)} at x=5,7,12\displaystyle {x}={5},{7},{12}..

x\displaystyle {x}5\displaystyle {5}7\displaystyle {7}12\displaystyle {12}
f(x)\displaystyle {f}'{\left({x}\right)}


Based on your table, f(x)\displaystyle {f{{\left({x}\right)}}} is until x=7\displaystyle {x}={7}, and is after.

The function f(x)\displaystyle {f{{\left({x}\right)}}} will have a at x=7\displaystyle {x}={7}.