a once-popular children's doll is slowly declining in popularity. the quartic function f(x)-0.002x^4 0.025x^3-0.364x^2-7.243x 86.993, where x is the number of years from 1993 to 2003. Estimate the number of dolls of this type that were sold (in thousands) during a given year from 1993 to 2003. Estimate how many dolls were sold in 2001.