Let's get rid of the fractions, and since they all have a common denominator, this can be done easily by multiply by 5.
After you multiply both sides of the equation by 5, you should get:
3n - 4 = 1n
Add 4 to both sides
3n = 1n + 4
Subtract 1n, or just n, on both sides
2n = 4
Divide by 2 on both sides
n = 2
