We are given the following function:
![f(x)=\sqrt[]{7x-21}](https://img.qammunity.org/2023/formulas/mathematics/college/250306qo2l1pfiscxxywjp3z8ae6xeydbf.png)
We are asked to determine its inverse function:

To do that, we will do the following change:

We get:
![y=\sqrt[]{7x-21}](https://img.qammunity.org/2023/formulas/mathematics/college/e8k387kjl8gum1cnc5v0afkci9jb611vea.png)
Now, since we want to determine the inverse we will swap variables, like this:
![x=\sqrt[]{7y-21}](https://img.qammunity.org/2023/formulas/mathematics/college/b16mizbjmrhtctguirgdizxa9wu07yj1hk.png)
Now we will solve for "y", first by squaring both sides:

Now we will add 21 to both sides:

Now we will divide both sides by 7:

This is the inverse function, therefore, we can do the following change:

We get:
