Answer
$\frac{9}{2}$
Work Step by Step
Step 1. Given $s=t^2+5t$ and $t=(u^2+2u)^{1/3}$, we have $\frac{ds}{dt}=2t+5$ and $\frac{dt}{du}=\frac{1}{3}(u^2+2u)^{-2/3}(2u+2)$
Step 2. $\frac{ds}{du}=\frac{ds}{dt}\frac{dt}{du}=(2t+5)(\frac{1}{3}(u^2+2u)^{-2/3}(2u+2))=(2(u^2+2u)^{1/3}+5)(\frac{1}{3}(u^2+2u)^{-2/3}(2u+2))$
Step 3. At $u=2$, $\frac{ds}{du}=(2(2^2+2(2))^{1/3}+5)(\frac{1}{3}(2^2+2(2))^{-2/3}(2(2)+2))=(2(8)^{1/3}+5)(\frac{1}{3}(8)^{-2/3}(6))=(9)(\frac{1}{12}(6))=\frac{9}{2}$
