Answer:
79
Step-by-step explanation:
171-1-91=170-91=79
Is that one or two questions?
Answer:
The explicit rule is:
Step-by-step explanation:
The explicit rule is given by:

The given sequence is 25,21,17,13

d=21-25
d=-4
We plug in the values into the formula to get;



Answer:
n
Step-by-step explanation:
-12n - (-13n) = -12n +13n = 1n