nomor 9 dan nomor 13 yaaa

[tex]\displaystyle 9\\f(x)=\frac13x^3-4x+a\\\\f'(x)\ \textgreater \ 0\\x^2-4\ \textgreater \ 0\\(x-2)(x+2)\ \textgreater \ 0\\x\ \textless \ -2\vee x\ \textgreater \ 2\\\\\boxed{\boxed{\text{HP}=\{x|x\ \textless \ -2\vee x\ \textgreater \ 2,x\in\mathbb{R}\}}}[/tex]

[tex]\displaystyle 13\\2^{2014}\mod7\equiv2^{2014\mod7}\mod7\\2^{2014}\mod7\equiv2^{5}\mod7\\2^{2014}\mod7\equiv32\mod7\\2^{2014}\mod7\equiv4\mod7\\\\4\text{ hari setelah hari Minggu adalah Kamis.}[/tex]