Answer
$y'=-27(4-3x)^8$
Work Step by Step
Find y and u:
$y=u^9$
$u=4-3x$
First, find the derivative of y and u. Don't forget to apply chain rule for y':
$y'=9u^8\times u'$
$u'=-3$
Then plug in u and u' into y':
$y'=9(4-3x)^8\times -3=-27(4-3x)^8$
