Check the picture below.

since the width is just a dimension unit, it can't be -31.
what is the length? well, the length is w + 30.
Basically what is happening is:
You start out with 15. That 1st week you have 22% more than 15, or in other words 15*1.22. The following week you have 22% more than 22% more of 15, which is 15*1.22*1.22.
Now we can write a function that models this situation:
f(n): number of views
n: number of weeks since you started
f(n) = 15(1.22^n)
We want to find out how many views there are after four weeks, so plug 4 in for n.
f(4) = 15(1.22^4)
f(4) = 33.23
This means after 4 weeks you can expect the video to have 33 views.
The answer is 250
100/2 = 50
50 * 5 = 250
Mean = it's really just another word for average. You add all the values up together, and divide the sum by the number of values there are. So here :
9 + 13 + 9 + 10 + 10 + 9 + 10 + 10 + 11 + 9 = 100
And now, you count how many values there are ^ up there. There are 10 values (just count how many numbers there are) and then you have to divide 100 by 10.
100 ÷ 10 = 10
Your MEAN is : 10
I hope this helps you
x'=2 y'=5
x"=0 y"= -4
slope. (2-0)=5-(-4)
slope. 2=5+4
slope =9/2