The domain is all possible input values for x
The only restriction is that we cannot divide by zero so
set 4x-3=0 and solve to find the restriction..
4x-3 = 0 add 3 to both sides
4x=3 divide both sides by 4
x = 3/4
The only restriction is x cannot equal 3/4 or .75
In interval notation this is: (-∞, 3/4)U(3/4, ∞)
The open parentheses denote that the value 3/4 and ∞ are not included.
If you are more comfortable with showing the domain as an inequality
[-∞ < x <3/4] U [3/4 < x < ∞]