Answers

2016-07-17T12:46:58+08:00
The formula for geometric sequence is an = a1(r)^n-1

1. 2, 10, 50...

a8 = 2(r)^8-1
a8 = 2(5)^7
a8 = 156, 250

2. 3 -9, 27, -81...

a8 = 3(r)^8-1
a8 = 3(-3)^7
a8 = -6561

3. 64, 16, 4...

a12 = 64(r)^12-1
a12 = 64(1/4)^11
a12= 64(1/4,194,304)
a12 = 1/65, 536

4. 8, 4 , 2...

a10 = 8(r)^10-1
a10 = 8(1/2)^9
a10 = 8(1/512)
a10 = 1/64
1 5 1