\[\boxed{\mathbf{14}\mathbf{.}}\]
\[y = f(x);\ \ x \in ( - 6;7).\]
\[\textbf{а)}\ f^{'}(x) = 0:\]
\[x = - 2;\ \ x = 4;\]
\[f^{'}( - 2) = 0;\]
\[f^{'}(4) = 0.\]
\[\textbf{б)}\ f^{'}(x) > 0:\]
\[при\ x \in ( - 6; - 2) \cup (4;7).\]
\[\textbf{в)}\ f^{'}(x) < 0:\]
\[при\ x \in ( - 2;4).\]