Determining the domain of a radical function

The video tutorial explains how to determine the domain of a function involving a radical expression. It covers solving inequalities, emphasizing the importance of flipping the sign when dividing by a negative number. The instructor uses a number line to illustrate the domain, showing that values of X must be less than 2/3. Examples are provided to verify the domain, demonstrating that numbers greater than 2/3 are not included.

What is the significance of the value 2/3 in the context of the function's domain?

How can you verify if a number is within the domain of the function?