Teslim is designing a cover for a book. He wants to have a rectangular grid with x^2 – 10x + 21 squares in it, for some positive whole number x. What are the possible side lengths for the grid? A. (x – 3) and (x – 7)
B. (x – 3) and (x + 7)
C. There are no possible whole number side lengths.
D. (x + 3) and (x + 7)

true

explanation:

the forst and 3rd

step-by-step explanation:

i dont know if you cant find a way its best to actually add all of them start from 105 tho

step-by-step explanation:

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for