The domain of a function is all values of x the function can have.
Since this function has radicals, and the value inside a radical needs to be positive or zero, and also the denominator of a fraction can't be zero, we have the following conditions:
![\begin{gathered} x-4\ge0 \\ x\ge4 \\ \\ x-6>0 \\ x>6 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/5oe8l2xabmz6w5u6jcp0483i0a6h8c96tk.png)
Since the first condition contains the second, so the domain set is represented by the second condition:
![(6,\text{inf)}](https://img.qammunity.org/2023/formulas/mathematics/college/hoy6w2drgs7gna3vmovw9fq69j0o0bh85s.png)