Question 1168777
1. This is a geometric sequence with common ratio, r = 36/12 = 12/4 = 3
The first term, a_1 = 4.
Thus the formula for the nth term is a_n = 4*3^(n-1)
2. a_n = a1*r^(n-1), so a_3 = a_1*r^2 = 1/25, and a_6 = a_1*r^5 = 1/3125
a_6/a_3 = r^3 = 25/3125 = 1/125 -> r = 1/5
Thus a_1 = 1/25/(1/5)^2) = 1
Therefore a_8 = (1/5)^7 = 1/78125
I trust you can complete the other two in a similar fashion...