Raul has 50 coupon books to sell. he must sell at least 10 coupon books to win a prize. the amount of money raul makes from selling x coupon books is represented by a function. f(x)=20xf(x)=20x what is the practical domain of the function? all integers from 10 to 50, inclusive all multiples of 20 between 0 and 1000, inclusive all real numbers all integers from 0 to 50, inclusive