Answer:
is one to one mapping, it is not onto mapping
Step-by-step explanation:

f₁(x) is one to one mapping
Let 
f₁(x) = f₁(y):
x₁³ = y₁³
f₁(x) is not onto mapping
Example: If f₁(x) = 7,
x₁³ = 7
![x_{1} = \sqrt[3]{7}](https://tex.z-dn.net/?f=x_%7B1%7D%20%3D%20%5Csqrt%5B3%5D%7B7%7D)
x₁ is not an element of Z
is one to one mapping, it is not onto mapping
A negative times a negative is a positive. I am not sure if that's the question, but hopefully that helps if it was.
This is an arith. sequence, and the common difference is -9.
a(n+1) = a(n)-9, with a(1)=8. Thus, if we look at the first term, we see 8; subracting 9 from 8 produces the second term (-1).
For question 2 it is 15
Because: 4 time 6 is 24 and then you minus 9 which is 15
So there you have it the answer is 15
Give me one sec to answer be back