Answer:
Step-by-step explanation:
Here, we want to get the formula that could be used to represent the rule of the sequence
From the given terms:
4th term is 9 and the 5th term is 15
6th term is 21, 7th is 27 and 8th is 33
What this means is that the difference between each of the terms is 6
Hence, we add 6 to the current term to get the next term
Thus:
Now, to get the first term, we can see that we are 3 differences away from the 3rd term
Hence, the value of the first term will be:
Thus, we have the first term as -9