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.

(a) 85,602,300

(b) 352,621,800

Step-by-step explanation:

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

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

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

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

solution:

the given function is ,

      =

the three roots of this quadratic function is , 0 ,8 and 10.all the roots are real and rational.

if a quadratic equation is of the form ,

sum of the roots = a + b +c= 0+8+10=18=  

product of roots taken two at a time = a b + b c+ c a = 0+80+0=80 =  

product of roots = a b c = 0=  

there are 11 doors in a hall starting from 0 to 11.the entry in the hall is permitted through gate number 0 and exit is allowed through only gate number 8 and 10.so, three roots(0,8,10) of quadratic function is given by entry and exit route of this hall.

600,000,000,000, or 6e14

step-by-step explanation: