Is 2 greater than 7? No so that means the whole number would stay 5.
Same for the other number. Then add the whole numbers attached to the fraction. Which is 6. Then go to the fraction. 2/7 + 2/7 is 4/7. This cannot be simplified anyfurther.
Answer: So, if it just magically doubles every 20 days, and its only been 15 days, then it would've started with 42, but I'm not sure since I can't see the original problem
If x=n then it would have 2 solutions because it would be x^2 = c which has a positive and negative solution but idk if that is what you are asking for