The first three terms of a geometric sequence are shown below.

what is the eighth term of the sequence?
a. -128x^8-384x^7
b. 128x^8+384x^7
c. 256x^9+768x^8
d. -256x^9-768x^8

Step-by-step explanation:

G.P. =

So, first term = a=x+3

Common ratio =

                       =

                       =

                       =

So, r = -2x

nth term of G.P. =

Substitute n = 8

Hence the eighth term of the sequence is  

step-by-step explanation:

b.) 160 miles on a 5 gallons car

step-by-step explanation:

240/10=24 miles/gallon

160/5=32 miles/gallon

30/1=30 miles/gallon

168/6= 28 miles/gallon

32 miles/gallon is the most amount, so this is the best.