How do you write an equation for the nth term of the arithmetic sequence: -3, -5, -7, -9, ...? Precalculus Sequences Arithmetic Sequences 1 Answer Shell · George C. Oct 30, 2016 #a_n=-2n-1# Explanation: The formula for an arithmetic sequence is #a_n=a_1 +(n-1)d# where #a_1# is the first term and #d# is the difference between terms. In this case #a_1=-3# and #d=-2# #a_n=-3+(n-1)(-2)=-3-2n+2 =-2n-1# #a_n=-2n-1# Answer link Related questions What is a descending arithmetic sequence? What is an arithmetic sequence? How do I find the first term of an arithmetic sequence? How do I find the indicated term of an arithmetic sequence? How do I find the #n#th term of an arithmetic sequence? What is an example of an arithmetic sequence? How do I find the common difference of an arithmetic sequence? How do I find the common difference of the arithmetic sequence 2, 5, 8, 11,...? How do I find the common difference of the arithmetic sequence 5, 9, 13, 17,...? What is the common difference of the arithmetic sequence 5, 4.5, 4, 3.5,...? See all questions in Arithmetic Sequences Impact of this question 5461 views around the world You can reuse this answer Creative Commons License