a/ \(y=2x^3-5\sqrt{x}+5x^{-3}\Rightarrow y'=6x^2-\frac{5}{2\sqrt{x}}-15x^{-4}=6x^2-\frac{5}{2\sqrt{x}}-\frac{15}{x^4}\)
\(\Rightarrow y'\left(4\right)=\frac{24241}{256}\)
b/ \(y=3x^3-x^2+6x-2\Rightarrow y'=9x^2-2x+6\)
\(\Rightarrow y'\left(4\right)=142\)
c/ \(y'=\frac{-11}{\left(3x-1\right)^2}\Rightarrow y'\left(4\right)=\frac{-11}{11^2}=-\frac{1}{11}\)