If you were asked to find the 87th term in a sequence, which formula would you want to be given?

To determine the nth term of sequence, first we need to know what type of sequence is it. It can be an arithmetic sequence or a geometric sequence. For an arithmetic sequence, the nth can be determined by the formula,

an = a1 + (n-1)d

For a geometric sequence, 

an = a1r^n-1

Hope this answers the question.