We start with the equation
\[
\frac{18}{x^{2}-3x}-\frac{6}{x-3}=\frac{5}{x}.
\]
First, we factor the polynomial in the denominator of the first term, \(x^{2}-3x\):
\[
x^{2}-3x = x(x - 3).
\]
Next, we rewrite the left side of the equation using partial fraction decomposition. We express
\[
\frac{18}{x(x - 3)} = \frac{A}{x} + \frac{B}{x - 3}.
\]
After performing the decomposition, we find:
\[
\frac{18}{x(x - 3)} = \frac{6}{x - 3} - \frac{6}{x}.
\]
Now, we substitute the partial fraction decomposition back into the original equation:
\[
\frac{6}{x - 3} - \frac{6}{x} - \frac{6}{x - 3} = 0.
\]
This simplifies to:
\[
-\frac{6}{x} = 0.
\]
The equation
\[
-\frac{6}{x} = 0
\]
implies that there are no solutions for \(x\) since the left-hand side cannot equal zero for any real value of \(x\). Thus, the solution set is empty:
\[
\text{Solution: } \emptyset.
\]