In Problems $45-60,$ find the indicated derivative and simplify.

$45.y^{\text{'}}$ if $y=3(x^2-2{)}^4$

$46.y^{\text{'}}$ if $y=2(x^{3}6{)}^5$

$47.\frac{d}{dt}2(t^{2}3t{)}^{-3}$