How to re-arrange the formula to make 'n' the subject

Hello

How do I rearrange this formula to make 'N' the subject?

((1.86x£1-£1)xN)+((-£1)x(100-N)) = £7.88

I know that the parenthesis might not make complete sense, but this is a formula I am using in Microsoft Excel which works fine. At present I have values for 'N' which give me £7.88. There are other occasions where I have the £ value result, but do not know 'N'.

It's a long time since I have had to rearrange something like this. There are 2 N's which confuses me. Thanks in advance.

Dan Wright