Arithmetic Sequence 1

Write an explicit formula for the sequence 7, 13, 19, 25, ...

•  $a_n=6+7n$  

•  $a_n=7n-1$  

•  $a_n=7+6n$  

•  $a_n=6n+1$  

Write an explicit formula for the sequence 94, 83, 72, 61, ...

• $a_n=85+11n$

• $a_n=105-11n$

• $a_1=94,\ a_n=a_{\left(n-1\right)}-11$

• $a_n=11n+83$

An arithmetic sequence has  $a_6=54$  and  $a_{11}=89$  , what is the value of  $a_{20}$  ?

• 159

• 143

• 152

• 154

 $a_1=3,\ a_n=2a_{\left(n-1\right)}+1$  is an example of a/an ____________ formula.

• recursive

• arithmetic

• explicit

• geometric

Write an explicit formula for 3, 5.5, 8, 10.5, ...

• $a_n=2.5n+0.5$

• $a_n=3+2.5n$

• $a_n=3n-0.5$

• $a_1=3,\ a_n=2.5+a_{\left(n-1\right)}$