Answer
$-9,-3,3,9,15,21$
Work Step by Step
Formula to calculate the nth term of an arithmetic sequence is: $a_n=a_1+d(n-1)$
Here, $a_1: $ First term and $d=$ common difference
Since, we have $a_1=-9$
Use a recursion formula to find the remaining five terms.
Then $a_2=a_1+6=-9+6=-3;\\a_3=a_2+6=-3+6=3;\\a_4=a_3+6=3+6=9;\\a_5=a_4+6=9+6=15;\\a_6=a_5+6=15+6=21$
Hence, the first six terms are: $-9,-3,3,9,15,21$
