How do u solve this?

[tex]\text{The domain}\\D:x\geq0[/tex]
[tex]3\sqrt{x}+5=0\ \ \ \ |-5\\\\3\sqrt{x}=-5\ \ \ \ |:3\\\\\sqrt{x}=-\dfrac{5}{3}\ FALSE\\\\\text{because}\ \sqrt{x}\geq0\ \text{for any values of x from the domain}[/tex]
[tex]Answer:\ x\in\O[/tex]