## Intermediate Algebra for College Students (7th Edition)

First three terms: $2,8,14$ last term: $116$ Sum of the an arithmetic series: $1180$
First three terms can be found as:$a_1=6-4=2;a_2=12-4=8;a_3=18-4=14$ Last term can be found as: $a_{20}=6(20)-4=116$ Sum of the an arithmetic series can be calculated by using formula $S_n=\dfrac{n}{2}(a_1+a_n)$ Here $n=20$ Thus, $S_{20}=\dfrac{20}{2}(2+116)=1180$ our results are: First three terms: $2,8,14$ last term: $116$ Sum of the an arithmetic series: $1180$