The domain of real numbers for the standard square root function is from [tex] [0,\infty)[/tex]
Standard square root function
[tex]f(x) = \sqrt{x}[/tex] <-------First Picture
When we add 6 to the x it shifts the functions to the left 6 spaces. See picture 2.
This make our domain now at [tex][-6, \infty)[/tex] <------Second Picture