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Work Shown:
[tex]a_1 = -13\\\\a_n = a_{n-1}+6\\\\a_2 = a_{2-1}+6 = a_1+6 = -13+6 = -7[/tex]
I added 6 to the first term (-13) to get the second term (-7)
The third term is found in a similar manner
[tex]a_n = a_{n-1}+6\\\\a_3 = a_{3-1}+6 = a_2+6 = -7+6 = -1[/tex]
Same for the fourth term as well
[tex]a_n = a_{n-1}+6\\\\a_4 = a_{4-1}+6 = a_3+6 = -1+6 = 5[/tex]
The first four terms are: -13, -7, -1, 5