Answer
The given equation $
\sqrt{3x+18}=x
,$ cannot have a negative solution since the left side of the equal sign is always a non negative number. Since the left side is equal to $x$, then $x$ cannot be a negative number.
Work Step by Step
$\bf{\text{Solution Outline:}}$
Use the fact that taking the even root of a non negative number is a positive number.
$\bf{\text{Solution Details:}}$
The given equation $
\sqrt{3x+18}=x
,$ cannot have a negative solution since the left side of the equal sign is always a non negative number. Since the left side is equal to $x$, then $x$ cannot be a negative number.