## Thomas' Calculus 13th Edition

$y'=-27(4-3x)^8$
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': $y'=9(4-3x)^8\times -3=-27(4-3x)^8$