To reduce the rational expression to its lowest terms, separate it as if it were a substraction of homogeneous fractions, this way:
[tex]\frac{3x-15}{3x}=\frac{3x}{3x}-\frac{15}{3x}[/tex]
Now, simplify each term:
[tex]\begin{gathered} \frac{3x}{3x}=1 \\ \frac{15}{3x}=\frac{5}{x} \end{gathered}[/tex]
Then, the simplified expression is:
[tex]1-\frac{5}{x}[/tex]
