Final answer:
The relationship between the number of days and the total number of baby hats can be represented by the equation h = 9d + 7.
Step-by-step explanation:
The seamstress already had 7 baby hats in her inventory. Then, she and her colleagues started knitting 9 more per day. Let d represent the number of days since starting to knit more hats and h represent the total number of baby hats. The relationship between the number of days and the total number of baby hats can be represented by the equation h = 9d + 7.