Question

Find the 20th term in the arithmetic sequence: 5, 12, 19, 26...

Answer 1

arithmetic sequence formula:

`a_n=a_1+(n-1)d`

where:

• an: nth term

,

• a1: first term

,

• n: term position

,

• d: common difference

In this case, the common difference is:

12 - 5 = 19 - 12 = 26 - 19 = 7

and the first term is 5. Then for n = 20:

`\begin{gathered} a_(20)=5+(20-1)7_{}_{} \\ a_(20)=138 \end{gathered}`