Problema Solution
use of the internet in a country is given by the function f(x)=0.485x2-1.694x+0.315 where the output is in million of users
in this formula x=6 corresponds to 1996,x=7 corresponds to 1997, and so on until x=20 corresponds to 2010
estimate when the number of internet users in the country reached 41 million
Answer provided by our tutors
When f(x) reaches 41 million,
41 = 0.485x2 - 1.694x + 0.315
0.485x2 - 1.694x - 40.685 = 0
By the quadratic formula:
x = 11.07 or x = -7.58.
Clearly we reject the negative answer, so x = 11.07. That happened in 1990 + 11.07 = year 2001.