## Calculus 10th Edition

The derivative is $\frac{-21}{x^8}$
This question involves a bit of algebraic rearrangement along with the power rule. y can be rewritten as $3*x^{-7}$. Using the power rule, we get $-7*3x^{-8}$ which can be rewritten as $\frac{-21}{x^8}$