14. Let $S _ { n }$ denote the sum of the first $n$ terms of an arithmetic sequence $\left\{ a _ { n } \right\}$ . If $a _ { 3 } = 5 , a _ { 7 } = 13$ , then $S _ { 10 } =$ $\_\_\_\_$ .
$\frac { 121 } { 3 }$
14. Let $S _ { n }$ denote the sum of the first $n$ terms of an arithmetic sequence $\left\{ a _ { n } \right\}$ . If $a _ { 3 } = 5 , a _ { 7 } = 13$ , then $S _ { 10 } =$ $\_\_\_\_$ .