How many terms are in the following sequence?
645700815, ..., 45, 15,5

17
18
19
16

18.

Step-by-step explanation:

It is a geometric sequence.

The common ration is 1/3.

The nth term of a GS is a1 r(n-1)

The first term of this GS is 645700815.

Substituting to see which term is 5:

Try 16:

16th term  = 645700815 * (1/3)^(16-1)

=  45

18th term =  645700815 * (1/3)^(18-1)

= 5.

So there are 18 terms.

answer: 0

step-by-step explanation: the positive, like 5, + its opposite, like -5 would be 0

5+(-5)=0, or 5-5=0