Question

The quadratic function f left parenthesis x right parenthesis equals 740.1 x squared minus 3109.2 x plus 945 approximates the growth of cell phone subscribers between 1985 and 2002 where x is the number of years past 1985 and f left parenthesis x right parenthesis is the number of subscribers in thousands. a. Use this function to approximate the number of subscribers in 1998. b. Use this function to predict the number of subscribers in 2009.

Answer 1

(a) 85,602,300

(b) 352,621,800

Explanation:

`f(x) = 740.1x^2 - 3109.2x+945`

(a) In 1998, x = 1998 - 1985 = 13

`f(13) = 740.1(13)^2 - 3109.2(13)+945 = 85602.3`

The number of subscribers in 1998 = 85602.3 × 1000 = 85,602,300

(b) In 2009, x = 2009 - 1985 = 24

`f(24) = 740.1(24)^2 - 3109.2(24)+945 = 352621.8`

The expected number of subscribers in 2009 = 352621.8 × 1000 = 352,621,800