# How do you find the domain of y=sqrt(9+x)?

the Domain of $y = \sqrt{9 + x}$ are all Real values of $x$ for which this equation is defined (within the Reals).
sqrt(9+x is defined for all values $x \ge - 9$
Therefore the Domain of $y = \sqrt{9 + x}$
is $\left[- 9 , + \infty\right)$