What is the next term in the geometric sequence -4,-12, 36 ?

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Answer 1 · 2018-06-05T11:17:39

#108# if the initial sequence is corrected to #-4,12,-36,...#

Lets check the terms...

#(-12)/-4=3#

#36/(-12)=-3# !!!!

There is not a comon ratio. the sequence must be

#-4, 12, -36,....#

In that case #r=-3# and first term #-4#, and then the next term is

#a_4=-36·(-3)=108#

so the general term is

#a_n=a_1r^(n-1)=-4·(-3)^(n-1)#