# How do you find the domain of the function: f(x) = sqrt(5-3x)?

$5 - 3 x \ge 0$
getting: $x \le \frac{5}{3}$
So your domain is all the real $x$ that are less or equal to $\frac{5}{3}$.
Note that the negative $x$ made me change the direction of my inequality.
You can have a look substituting values of $x$ to confirm this;
try $x = 2 \left(> \frac{5}{3}\right)$ (which is not acceptable) and $x = 1 \left(< \frac{5}{3}\right)$ (which is ok) to confirm our reasoning.