(a) t(mMAX) =? $$ \begin{aligned} \dot m &= \dxt{m} = \dt\(5.00t^{0.8}-3.00t + 20.00\) = 0 \\ &= \frac{4}{\sqrt[5]{t}}-3 = 0 \end{aligned} $$ $$ \begin{aligned} \\ t &= \frac{1024}{243}\ut{s} \\ &\approx 4.2139917695473251029\ut{s} \\ &\approx 4.21\ut{s} \end{aligned} $$ (b) mMAX =? $$ \begin{aligned} m(t_{MAX}) &= 5.00(t_{MAX})^{0.8}-3.00(t_{MAX}) + 20.00\ut{g} \\ &= 5.00\(\frac{1024}{243}\)^{0..