We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive pseudonymised information about your use of our website. cookie policy and privacy policy.
 
+0  
 
+1
129
1
avatar

The sequence 6,-9,x,y is such that the first three terms form an arithmetic sequence and the last three terms form a geometric sequence. Find x and y.

Express your answer as x,y

 Feb 23, 2019
 #1
avatar+104648 
+2

The common difference is second term - first term =   - 9 - 6 =   - 15

 

So the third term is  -9 - 15  = -24

 

And the common ratio   is  third term / second term =   -24 /-9 =  8/3

 

So....the fourth term is   -24 (8/3) =  -64

 

So   x , y   =      -24, -64  

 

 

cool cool cool

 Feb 23, 2019

15 Online Users

avatar