The fifth term of an arithmetic sequence is 9 and the 32nd term is -84. What is the 23rd term?
From 5th to 32nd is 27 terms 27 of the common diference, d
From 9 to -84 is - 93 and is 27 of d -93/27 = d
from 5th to 23rd = 18 terms or 18 d's added to 9
9 + 18 (-93/27) = -53