Unless there is a domain restriction for the function, the domain of a function is all real numbers. This means that all we need to do is determine whether there is a domain restriction.
The things that cause a domain restriction are: an x in the denominator of a fraction like or a radical like
As there are no variables in the denominator or a radical, we can conclude that the domain of this function is all real numbers.
When Im using N is equal to numerator and D for denominator, in order to get the fraction we substitute and the results combine in the fraction like this