What is this answer?

Question

A​ once-popular children's doll is slowly declining in popularity. The quartic function

f(x)=−0.022x4+0.457x3−2.492x2−5.279x+87.419,

where x is the number of years since​ 1993, can be used to 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 2002. The number of dolls sold in 2002 was approximately ?

Answer 1

Hello, Bristan,

As Mark M. has suggested, x in this equation is the number of years since 1993. He says use 8, but I'm wondering if 9 is the correct number, since (2002-1993) = 9. But I may be counting incorrectly. If 9, the equation would look like this:

f(9) = −0.022*(9)⁴+0.457*(9)³−2.492*(9)²−5.279*x+87.419

If is is the correct number, then use "8" in place of the "9."

For 9, the number should be a little under 27,000, I estimate.



Bob