What is the recursive rule for an=4n−1? a1=4; an=an−1−1 a1=3; an=an−1+4 a1=−1; an=an−1+4 a1=3; an=an−1−1

Plug in n = 1 into the nth term formula
a(n) = 4n-1
a(1) = 4*1-1
a(1) = 3
So the first term is 3

The second term will be 7 because we add on 4 each time, as indicated by the slope of 4. This is also known as the common difference.

So the nth term is found by adding 4 to the (n-1)st term, in other words,
a(n) = a(n-1)+4



In summary, the answer is 
a1=3; an=an-1+4
which is choice B