Respuesta :

Apocrophon
The pattern increases by 4, then 6, then 8
Since the rate is changing, the function has a square in it.
If you plug 1, 2, and 3 into the functions below, [tex] n^{2} +n[/tex] is the one that works.

The answer is [tex] n^{2} +n[/tex]
13) Here, Sequence : -2, -6, -18, -54
Common Ratio = a₂/a₁ = -6/-2 = 3
As the expression is in negative sign, it's sequence will be -3ˣ
Where x = number of terms in the sequence [ By this rule, you can calculate the unknown nth number]

In short, Option C is your answer!!!!

14) Here, a₂-a₁ = 6-2=4, a₃-a₂ = 12-6 = 6
So, difference is increasing by 2 at each step, as it's not arithmetic, It must deviate by the square on it. As only one option has square on it, it will be
 (n²+n)

In short, Option B is your final answer.

15)V = 2πr²h
 h = V / 2πr²

In short, Option D is your final answer.

Hope it helped, Please Let me know, if you have some doubts!!