
You can see it's a geometric sequence because the ratio is constant (

).
The nth term of a geometric sequence:


It has to be the sum for term 4 through term 15, so n=4 and the number above the sigma is 15.
Your answer:
Answer:
x>3
Step-by-step explanation:
We are given with the inequation 3(8-4x) < 6(x - 5)
Dividing both sides in the above in equation by 3 we get
(8-4x)<2(x-5)
Distributing 2 over (x-5)
(8-4x)<2x-10
8-4x<2x-10
adding 10 and 4x on both hand sides we get
8+10<2x+4x
18<6x
Dividing both sides by 6 we get
3<x
Hence the solution to the given in equation is x>3