### Home > APCALC > Chapter 3 > Lesson 3.1.2 > Problem3-33

3-33.

Expand and evaluate the following sums.

1. $\displaystyle\sum _ { i = 2 } ^ { 6 } ( 3 i )$

$\text{Factor out the }3:\:=3\displaystyle \sum_{i=2}^{6}i$

$=3( 2+3+4+5+6)=3(20)=60$

1. $\displaystyle\sum _ { i = 1 } ^ { 10 } ( 5 + \frac { 1 } { 2 i } )$

How can this sum be rewritten to save you time?