All your answers look good!
a.
In order to find the common ratio, we just need to divide a term by the term that comes before it.
So using the terms 20 and -5, we have:

b.
The recursive rule can be found with the formula:

Where an is the nth term and q is the ratio. So we have:

c.
The explicit rule can be written as:

Where an is the nth term, a1 is the first term and q is the ratio. So:
I believe you combine the first and last terms first because they have the same denominator
Answer:
pretty sure it's 360 :)
Step-by-step explanation:
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Answer:
105
Step-by-step explanation:
500 goes into 100, 5 times
21 times 5 is 105
So 21/100 is equal to 105/500
Or you can do
500*0.21=105