Answer:
IS IT AN ARITHMETIC SEQUENCE OR NOT?
1. 3,6,9,12
Ans: Yes (it's an arithmetic sequence)
Common difference: 3
2. -5,2,-1,4
Ans: No (it's not an arithmetic sequence)
3. 1,2,5,10
Ans: No
4. 8,3,-2,-7
Ans: Yes (it's an arithmetic sequence)
Common difference: -5
5. -7,-4,-1,2
Ans: Yes (it's an arithmetic sequence)
NOW,
How to identify if it's an arithmetic sequence?
Ans: Simply find it's COMMON DIFFERENCE
How to find common difference?
All you have to do is to subtract the second term to the first term
The equation is d = a₂ - a₁ or a₃ - a₄ and so on
Ex.
3,6,9,12
Solution: d = a₂ - a₁
d = 6 - 3
d = 3
Let's try to see if it's the same for others
d = 9 - 6
d = 3
Therefore it's an arithmetic sequence.
