1. which best describes the relationship between the successive terms in the sequence shown?

9, –1, –11, –21, …

a)the common difference is –10.
b)the common difference is 10.
c)the common ratio is –9.
d)the common ratio is 9.

2. a sequence is defined recursively using the formula f(n + 1) = f(n) – 5 . which sequence could be generated using this formula?

a)1, –5, 25, –125,
b)2, 10, 50, 250,
c)3, –2, –7, –12,
d)4, 9, 14, 19,