The function f(x)=2x+1 is defined over the interval [2, 5]. if the interval is divided into n equal parts, what is the value of the function at the right endpoint of the kth rectangle?

  D.  5 +6k/n

Step-by-step explanation:

The width of the interval is (5 -2) = 3. The width of one of n parts of it will be ...

  3/n

Then the difference between the left end point of the interval and the value of  x at the right end of the k-th rectangle will be ...

  k·(3/n) = 3k/n

So, the value of x at that point is that difference added to the interval's left end:

  2 + 3k/n

The value of the function for this value of x is ...

  f(2 +3k/n) = 2(2 +3k/n) +1 = (4 +6k/n) +1

  = 5 +6k/n

if you use photomath right away it will give you the answer not like this app that you have to wait for people.

let's cover over the formula of the vertex:

y = a(x – h)^2 + k

in this formula, (h,k) are the vertex, always remember that the positive or negative value of the vertex is based on the sign it has.

for example, if the vertex is -3,-6 then both the x and y value would have the positive sign attached to it and if it were a positive x and y value, then a negative sign would be attached to it.

with that being said, for our problem the x value is a positive one so we are looking for a number with a negative sign next to it, in this case the first and second choice.

however, for the first answer choice it isn't quite part of the formula so we know that the answer choice correctly displays the x value.

to confirm, we can see if the -1 fits correctly with the second answer choice, and as mentioned above a negative number will have a positive sign attached to it. so, for our problem we can see that -1 has been changed to +1, so we can confirm that the second answer choice is correct.

hence, our final answer is y=(x - 1)^2 + 1