5n - (3 - 4n)...u have to distribute through the parenthesis...and if it helps, if u have a sign by itself, there is always a 1 by it, even if it is not written.
So if it makes it easier, write ur equation like this...
5n - 1(3 - 4n)...now take that -1 and multiply it by every number in the parenthesis to get rid of the parenthesis
5n - 3 + 4n ...combine like terms
9n - 3 <==