Answer
(a) 45
(b) 24
(c) 99
Work Step by Step
Recall: \begin{equation}\sum_{i=m}^{n}C=C(n-m+1)\end{equation}
(a) \begin{equation}\sum_{i=1}^{5}9=9(5-1+1)=45\end{equation}
(b) \begin{equation}\sum_{i=0}^{5} =4(5-0+1)=4\times6=24\end{equation}
(c) \begin{equation}\sum_{k=2}^{4}k^{3}=2^{3}+3^{3}+4 {3}=8+27+64=99\end{equation}
