Determine the Average Value Of $f ( x ) = e ^ { 3 x }$

Short Answer

Determine the average value of $f ( x ) = e ^ { 3 x }$ over the interval from x = 1 to x = 3.
Enter your answer in the form a( $\mathrm { e } ^ { \mathrm {b} }$ ± $\mathrm { e } ^ { \mathrm { C } }$ )