Evaluate Each Sum That Exists $\sum_{i=1}^{25}(20-3 i)$ (B) $\sum_{i=1}^{6} \frac{4}{3}(3)^{i}$ (C) $\sum_{i=1}^{\infty} 3\left(\frac{5}{4}\right)^{i}$

Short Answer

Evaluate each sum that exists.
(a) $\sum_{i=1}^{25}(20-3 i)$
(b) $\sum_{i=1}^{6} \frac{4}{3}(3)^{i}$
(c) $\sum_{i=1}^{\infty} 3\left(\frac{5}{4}\right)^{i}$
(d) $\sum_{i=1}^{\infty} 5\left(\frac{4}{5}\right)^{i}$