Camilla borrows a book from the library for ddd days. the library charges a late fee of 0.100.100, point, 10 dollars per day that the book is late.
if camilla returns the book more than 212121 days after she borrowed it, the expression 0.10(d-21)0.10(d−21)0, point, 10, left parenthesis, d, minus, 21, right parenthesis represents the total late fee camilla owes.
what does (d-21)(d−21)left parenthesis, d, minus, 21, right parenthesis represent in this context?