Rational: Any number that can be expressed as a fraction (or a ratio.)
Irrational: Not rational, any number that can't be written down as a fraction. Some examples include

,

, and so on.
Answer:
The first four terms of the sequence are-6, -2, 2 and 6
Step-by-step explanation:
The given sequence is 
In order to find the first four term of the sequence we put n =0, 1, 2 and 3.
For n =0

For n =1

For n =2

For n =3

Therefore, the first four terms of the sequence are
-6, -2, 2 and 6
Step-by-step explanation:
If the tickets given to employees = 40
Then tickets given to listeners = 2 x no of employees tickets
= 2 x40 = 80
Total tickets = 40+ 80 = 120
(a^3)^2
= a^(3*2)
= a^6
or
a^3 * a^3
= a^(3+3)
= a^6