Saturday, August 7, 2010

Supose that N=x + 4 models the number of cases of an infection, im millions, of a disease x years from now

A) Approximately how may cases of the infection will there be 16 years from now?





B) In approximately how may years will there be 6 million cases?Supose that N=鈭?x + 4 models the number of cases of an infection, im millions, of a disease x years from now
how many cases are there now? What is N now?Supose that N=鈭?x + 4 models the number of cases of an infection, im millions, of a disease x years from now
a) 8





b) (6-4)^2 = 2^2 = 4
for (a), they say that x=16, since x is the number of years.


so the number, in millions, of infected people will equal (sqrt)(16)+4. Use your calculator to reduce this, and that is how many million people will be infected in 16 years.





In (b), N=6 because there will be 6 million people infected. So:


6=sqrt(x) +4


Subtract the 4.


2=sqrt(x)


x=4.





I couldn't tell in this equation if it was N=sqrt(x) + 4 or N=sqrt(x+4). If it was the last one I mentioned, you would still use the same methods in both problems, except that in the second equation, you would square both sides to get rid of the square root BEFORE you subtracted the 4.


Hope this helped!

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