9 is subtracted from the product of 5 and a number
Sin (2 pi/3) = sqrt(3)/2
you can get this from the unit circle
X=4 because when you square 4 you get 16! Aka 4x4=16. Also the other one is 16 divided by 4. Hope this helped
This is an arithmetic sequence because the difference
between the terms in the sequence remain constant.
In other words, we subtract 9 from one term to get the next.
So we start off with the explicit formula, shown below in yellow.
"n" will be the number of terms in the sequence,
a1 will be the first term in the sequence,
and d will be the common difference.
Now substitute these in like I have below.
You will get -425 as an answer.