Split mixed sigma sums into arithmetic and geometric parts

Find (i) $\sum_{k=0}^n(k+n+1)$ in terms of $n$; (ii) $\sum_{r=1}^N(4r+2^{-r})$ in terms of $N$; (iii) $\sum_{k=1}^{30}(a^{2k}+ka)$ in terms of $a$.