Find the common difference of the arithmetic sequence
-17, -15, -13, ...

term 1 - term 2 = sequence

so

-17-(-15) = -2

and if you minus the rest by -2 it will give you the next term

-15-(-2) = -13

-13-(-2) = -11

walter needs to make at least 5 more cookies but no more than 40. 5 ≤ x ≤ 40

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40