Find all relative extrema of the function. Use the Second Derivative Test where applicable. (If an answer does not exist, enter DNE.) PLEASE HELP!!!!

Answer: (0, -9)
Given:
[tex]f(x)=x^{\frac{6}{7}}-9[/tex]First, we derive the given equation:
[tex]\begin{gathered} \frac{d}{dx}x^{\frac{6}{7}}-9 \\ =\frac{6}{7x^{\frac{1}{7}}} \end{gathered}[/tex]The intervals would be:
[tex]-\inftyPlugging x=0 to f(x):[tex]\begin{gathered} f(x)=x^{\frac{6}{7}}-9 \\ f(0)=(0)^{\frac{6}{7}}-9 \\ f(0)=-9 \end{gathered}[/tex]Therefore the relative minimum is at (0, -9)