# How to find domain for f(x) = x^2+3?

The domain is the whole set $\setminus m a t h \boldsymbol{R}$.
The domain of a function is the set of value you can give as input to the function. Now, your function takes a number $x$, squares it (${x}^{2}$), and then adds $3$: (${x}^{2} + 3$).
The question is: is there any number which can't be squared? And the answer is no: we can square any real number, since it is always a legit operation. Needless to say, we can also always add $3$ to any number. So, there are no numbers to exclude from the domain.