~Hello There!~
This is the equation:
[tex]3+\sqrt{x+7} -\sqrt{3x}[/tex]
Simply substitute 9 into wherever you see 'x'
[tex]3+\sqrt{(9)+7} -\sqrt{3(9)}[/tex]
The answer you get is:
[tex]7-3\sqrt{3}[/tex]
Hope This Helps You!
Good Luck :)
Have A Great Day ^_^
- Hannah ❤