# What is the domain of the function: f(x) =sqrt(x-9)?

Domain is $x \ge 9 \mathmr{and} \left[9 , \infty\right)$
f(x)= sqrt(x-9) ; f(x)  is undefined for $x < 9$
Therefore domain is $x \ge 9 \mathmr{and} \left[9 , \infty\right)$