I re-wrote the denominator like this:
3y+4/y - 3/1
From here I just cross multiplied:
3y + 4 - 3y
Combine like terms and you end up with 4/4.
F(3y+4/y) = 1
The easiest way is to multiply both sides of the equation by the denominator. The reason why this works is because it doesn't change the equality.
(5x+10)/2 = 20
5x+10 = 40
5x = 30
x = 6
Even if the variable was in the denominator, you can still solve for the variable using the same steps...