Can someone me on this question? ?

You need to divide the coefficient of n to all sides so that n is isolated.
You will get -5<n≤2.
This means that n  can be any real number from -5 to 2. 
So you can include any number from only that range, like -3 or 1. It cannot be -5, but it can be 2 because of the ≤ sign. 

Yes you do, so £1973.09 - £1473.50 = £499.59 so tim overpaid £499.59 .hope this ; )