Answer:
a7=4/3 or a7=-4/3
Explanation:
using the geometric sequences formula
an=ar^n-1
a2=ar
a4=ar³
when a2=324 and a4=36
324=ar...........(1)
36=ar³............(2)
from equation (1) a=324/r substitute in equation (2)
we have :
36=324/r *r³
36=324r²
r²=36/324
r²=1/9
r=±1/3
substitute when r=±1/3 in (1)
324=a(±1/3)
a=±972
so the 7th term is
when r=±1/3
we have
a7=ar^6
a7=±972(±1/3)^6
a7=972/729
a7=4/3 or a7=-4/3