N-3n=14-4n
or can be written as follows
1n-3n=14-4n
becomes
-2n =14-4n
then add 4n to both sides of the equation, on the right the 4n's cancel out and on the left side -2n+4n = 2n
so
2n=14
divide both sides of the equal sign by 2 to get the n by itself
n=7
if you plug 7 in for n in the original equation it should equal the same on both sides of the equal sign