Answer
The given sequence is arithmetic sequence and the common difference = 1.
Work Step by Step
The given general term is $a_{n}$ = n + 5
First term $a_{1}$ = 6 (if n=1)
Second term $a_{2}$ = 7 (if n=2)
Third term $a_{3}$ = 8 (if n=3)
Forth term $a_{4}$ = 9 (if n=4)
Difference of consecutive terms.
9 -8 = 1.
8 - 7 = 1.
7 - 6 = 1.
From above we observe that the difference between two consecutive terms is constant. So the given sequence is arithmetic sequence and the common difference = 1.
