Answer:
27 terms
Step-by-step explanation:
Here the first term is 7 and the common difference is -7. Each new term is equal to the previous term, less 7.
The general formula that involves first and last terms, common difference and number of terms is last = first + (n - 1)(common difference)
We substitute the knowns, as follows:
-175 = 7 + (n-1)(-7)
Solve this first for n-1, and then for n:
Subtract 7 from both sides: -182 = - 7(n-1)
Dividing both sides by -7 yields 26 = n - 1
Then n = 27.
There are 27 terms in this arith. sequence.
