(4,7,12,19) how do you right this in recursive and explicit pls

You can see how the difference between two consecutive terms is constantly increasing:

So, for the next terms we'll have to add +9, +11, +13 and so on.

Also, note that is obtained by adding the 2nd odd number to , is obtained by adding the 3rd odd number to , and so on.

So, the recursive formula is

For the explicit formula, recall that the sum of the first n odd numbers is n squared. Taking into account the fact that we're not starting from 1, we have

i just took the test, the correct answer is .. 31.5 in.

step-by-step explanation:

you can add the two numbers and divide the result by 2. or you can find the gap between the two numbers and add half of this to the smaller number.