Th equation is:
[tex]y=gx+n[/tex]We need to solve for n.
It means, to find an expression of the form n = something.
We need to isolate n.
In the expression, if we get rid of "gx" from the right-hand side, we can isolate n.
For this, we subtract "gx" from both sides.
Then, we get our answer.
Shown below:
[tex]\begin{gathered} y=gx+n \\ y-gx=gx+n-gx \\ y-gx=n \\ or \\ n=y-gx \end{gathered}[/tex]