Question 178546
<font face="Times New Roman" size="+2">

I presume you mean the model to be *[tex \Large N = x^2 + 2]  ('^' does not mean 'squared', it means 'raise to the power of' and you have to specify the power.  If you mean squared, then you need to write 'x^2'  Ok?)



*[tex \Large \text{          } N = x^2 + 2]


Substitute 7 for N:


*[tex \Large \text{          } 7 = x^2 + 2]


Add -2 to both sides:


*[tex \Large \text{          } 7 - 2 = x^2]


*[tex \Large \text{          } 5 = x^2]


Take the positive square root:


*[tex \Large \text{          } x = \LARGE sqrt{5}] years.


That is the exact answer.  A numerical approximation is two years, two months, and 25 days.



</font>