8 time the 8 term is equal to 12 times the twelve term.find the 20th term??

1 answer

8(a+7d) = 12(a+11d)
8a+56d = 12a+132d
4a = -76d
a = -19d

So, there are many such sequences:

-19,-18,-17,-16,-15,-14,-13,-12,-11,-10,-9,-8
8(-12) = 12(-8)

38,36,34,32,30,28,26,24,22,20,18,16
8(24) = 12(16)