[tex]y=e^{3x-1}-7\Rightarrow y'=\left({e}^{3\,x-1}\right)'-\left(7\right)'{e}^{3\,x-1}\cdot \left(3\,x-1\right)'-0=\\={e}^{3\,x-1}\cdot \left(3\cdot 1-0\right)-0=3\,{e}^{3\,x-1}\\y\left ( \frac{1}{3} \right )=3e^{3\cdot 1/3-1}=3e^{1-1}=3[/tex]