Help#1 ​

1.  No...in a geometric series.the ratio between the successive term to the previous term must be constant ....note that

-4 / 2   =   -2

But

-16 / - 4  =  4    so....not geometric

2. Fifth term  

The common ratio  is  36/120  =  3/10

So....the fifth term is

First Term * (Common Ratio)^n-1   =

120 (3/10)^5-1  =

120 (3/10)⁴   = 

 0.972