11) -104 = 8x
12) 14b=-56
13) -6 = b/18
14) 10n = 40

11) -104÷8=x

-13=x

x=-13

12) b=-56÷14

b=-4

13) -6×18=b

b=-108

14) n=40÷10

n=4

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