We have the equation of y as a function of x:

To find x(y) we just need to solve for x, first by subtracting m from both sides

Now, we just have to take the square root on both sides
Taking the square root of a number it's actually raising it to the 1/2 power:
![\sqrt[]{a}=a^{(1)/(2)}](https://img.qammunity.org/2023/formulas/mathematics/college/aj72c2oh217b34e7bv5di02cofpt618cc1.png)
Now, when we proceed to raise the square root of a number to two, we can arrange it like this:

When we take the square root of a number that is raised to two the result will be the number without any power, like this:
![\sqrt[]{a^2}=a](https://img.qammunity.org/2023/formulas/mathematics/college/grno7s8qscc4w70ciz3ve8u9f07avr4hwy.png)
Then:
![\sqrt[]{x^2}=x=\sqrt[]{y-m}](https://img.qammunity.org/2023/formulas/mathematics/college/awbgnwzjgdvp34or11rj57m6bycf9ppzi3.png)