Answer
$=-\frac{7}{3}x^{6}-\frac{2}{3}$.
Work Step by Step
Distribute the $-\frac{1}{3}$ through to get $-\frac{1}{3}x^{7}-\frac{2}{3}x+3$. Finally, use the power rule for derivatives ($[x^{n}]'=nx^{n-1}$) to get $-\frac{7}{3}x^{7-1}-\frac{2}{3}+0=-\frac{7}{3}x^{6}-\frac{2}{3}.$
