The fifth term of an arithmetic sequence is 9 and the 32nd term is -84. What is the 23rd term?
+128407
We have that
a1 + 4d = 9 and
a1 + 31d = -84 where a1 is the first term and d is the common difference between terms
Subtract both equations
- 27d = 93 divide both sides by -27
d = - 93 / 27 = -31/ 9
And.....there are 18 terms between the 5th term and the 23rd term......so we have....
9 + 18(-31 / 9) = 9 - 62 = -53 = 23rd term
+128407
We have that
a1 + 4d = 9 and
a1 + 31d = -84 where a1 is the first term and d is the common difference between terms
Subtract both equations
- 27d = 93 divide both sides by -27
d = - 93 / 27 = -31/ 9
And.....there are 18 terms between the 5th term and the 23rd term......so we have....
9 + 18(-31 / 9) = 9 - 62 = -53 = 23rd term
