How do you do this problem?

400

Step-by-step explanation:

│an − L│< ε

│2 + (-1)ⁿ/√n − 2│< 1/20

│(-1)ⁿ/√n│< 1/20

1/√n < 1/20

√n > 20

n > 400

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