SOLUTION: There are two questions to this, but I believe I answered the first part correctly. 1a.)Suppose that N=sqrt x+2 models the number of cases of an infection, in millions, of a disea

Algebra ->  Square-cubic-other-roots -> SOLUTION: There are two questions to this, but I believe I answered the first part correctly. 1a.)Suppose that N=sqrt x+2 models the number of cases of an infection, in millions, of a disea      Log On


   

Question 206036: There are two questions to this, but I believe I answered the first part correctly.
1a.)Suppose that N=sqrt x+2 models the number of cases of an infection, in millions, of a disease x years from now.
How many cases of the infection will there be 16 years from now?
My answer is: N=sqrt x+2
sqrt(16)=4
sqrt(16)+2=6
6 million cases in 16 years.
1b)In how many years will there be 7 million cases?
Part b is what I need help with. Will you please show me this step by step?
Thank you for your help.
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
You are correct on part 1a)
For part b, you need to set N = 7 (for 7 million) and solve for x, (the number of years from now).
7+=+sqrt%28x%29%2B2 Subtract 2 from both sides.
5+=+sqrt%28x%29 Finally, square both sides.
25+=+x
There will be 7 million cases 25 years from now.