Loading [MathJax]/jax/output/SVG/jax.js
 
+0  
 
+1
859
2
avatar+239 

The fifth term of an arithmetic sequence is 9 and the 32nd term is -84. What is the 23rd term?

 Dec 5, 2018
 #1
avatar+6250 
+1

an=a1+(n1)da5=a1+4d=9a32=a1+31d=84subtract a5 from a3227d=93d=9327=319a1=94d=94(319)=9+1249=2059a23=a1+22d=2059+22(319)=53

.
 Dec 5, 2018
 #2
avatar+26397 
+11

The fifth term of an arithmetic sequence is 9 and the 32nd term is -84.
What is the 23rd term?

 

Formula of an arithmetic sequence:

|aiajakijk111|=0ai(jk)+aj(ki)+ak(ij)=0

 

Set i=5 j=32 k=23 Set ai=a5=9 aj=a32=84 ak=a23 

 

ai(jk)+aj(ki)+ak(ij)=09(3223)+(84)(235)+a23(532)=09(9)+(84)(18)a23(27)=081151227a23=027a23=81151227a23=1431a23=143127a23=53

 

laugh

 Dec 6, 2018

5 Online Users