Juan has 20 books to sell. he sells the books for $15 each. the amount of money juan makes from selling x books is represented by a function. f(x)=15xf(x)=15x what is the practical range of the function? all multiples of 15 between 0 and 300, inclusive. all integers from 0 to 20, inclusive. all multiples of 20 between 0 and 300, inclusive. all real numbers.