Answer:
The common difference would be -6.5
Step-by-step explanation:
Given sequence,
9, 2.5, -4, -10.5, -17, ...
Since,
2.5 - 9 = -4 - 2.5 = -10.5 + 4 = -17+10.5 ... = -6.5
Thus, 9, 2.5, -4, -10.5, -17, ... is an AP,
In an AP the difference between any two consecutive terms is called the common difference.
Hence, the common difference would be -6.5
