The fifth term of an arithmetic sequence is 9 and the 32nd term is -84. What is the 23rd term?
9 =F + 4D, -84 =F + 31D, solve for F, D
F =205 /9 - This is the first term.
D = - 31/9 - This is the common difference
23rd term =205/9 + ( - 31/9 * 22)
23rd term = -53