Answers:
9 books
6 days
Step-by-step explanation:
The given equation is
y = x² - 12x + 45
So, the graph of this equation is
Then, the minimum point of the graph is (6, 9). It means that the minimum number of books sold was 9 books and it was 6 days after the autograph-signing reception
So, the answers are:
9 books
6 days