## Calculus 8th Edition

$B'(y) = -6cy^{-7}$
$B(y)=cy^{-6}$ lets use the Formula $(cf)'=cf'$ then $B'(y) = (cy^{-6})' = c(y^{-6})'$ and the Formula $(x^{n})'=nx^{n-1}$ then $B'(y) = (cy^{-6})' = c(y^{-6})'=c (-6y^{-7})=-6cy^{-7}$