Use of the Internet in a country is given by the function f(x)=0.485x^2-1.694x+0.315, where the output is in millions 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 13 million.

Question

Use of the Internet in a country is given by the function f(x)=0.485x^2-1.694x+0.315, where the output is in millions 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 13 million.
The number of Internet users in the country reached 13 million during the year?

Henry · Answer

F(x) = 0.485x^2 - 1.694x + 0.315 = 13.

0.485x^2 - 1.694x - 12.685 = 0,
X = 7.15 Which corresponds to 1997.
Therefore the number of Internet users reached 13 million in 1997.

Use Quadratic Formular to solve Eq.