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 2001.The number of dolls sold in 2001 was approximately ?

​(Round to the nearest​ thousand.)

Answer 1

Hi Bristan,

The problem is:

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

For this problem, we just need to find x, which will be the number of years after 1993, and plug it into the equation.

It is asking how many dolls were sold in 2001. To find out how many years 2001 is after 1993 we just subtract 1993 from 2001,

2001 - 1993 = 8 years after 1993

x = years after 1993

x = 8

Then you just plug in f(8) to get,

f(8) = −0.022(8)⁴ + 0.457(8)³ − 2.492(8)² − 5.279(8) + 87.419

Let me know if this helped!