Me get the answers. i don't understand it

Number 14:
When looking at the table, the x has an increase of 3 while the y is an increase of 6. We need to divide the difference of the y by the difference of x.
6/3=2
So, that means every time x changes by one, y changes by 2. At 9, the corresponding number is 15. Since we’re to 10, the corresponding number has to be 17.
So, the answer is b, 17.

Number 15:
This problem deals with perimeter. No matter what, the perimeter is 12 feet.
To find perimeter, it is 2l+2w=12
We have the length, so let’s put it in.
2(4.5)+2(w)=12
Let’s multiply.
9+2w=12
We need w by itself, so we need to subtract 9 from both sides then divide by 2.
2w=3
3/2=1.5
The answer is A, 1.5.

I’m not absolutely sure but i think it’s 7x6x5x4x3x2=5040 because as the first character you can take any of the 7 given then you are left with 5 then 6 then 4 etc.