Question 350743
f(x)=~(13-x)

The domain of an expression is all real numbers except for the regions where the expression is undefined.  This can occur where the denominator equals 0, a square root is less than 0, or a logarithm is less than or equal to 0.  All of these are undefined and therefore are not part of the domain.
(-x+13)<0

Solve the equation to find where the original expression is undefined.
x>13

The domain of the rational expression is all real numbers except where the expression is undefined.
x<=13_
-I,13 is your answer...so yes, C is correct due to the undefined regions