Answer
domain: $(-\infty, 3)$
Work Step by Step
The restriction for the domain of a logarithmic function is that its argument must be positive.
Domain: all $x$ for which $3-x>0$.
$3-x>0\qquad/+x$
$3>x$
(x is any number less than 3)
In interval notation,
domain: $(-\infty, 3)$
