The symbol "⁝" is not a standard mathematical operator, so its meaning is unclear. However, if we assume you meant to use a colon ":" to represent a ratio, then the expression \((3x + 9) : (2x + 1)\) can be interpreted as the ratio of \(3x + 9\) to \(2x + 1\).

To simplify this ratio, you can write it as a fraction:

\[
\frac{3x + 9}{2x + 1}
\]

This fraction represents the ratio of the polynomial \(3x + 9\) to the polynomial \(2x + 1\).

If you want to simplify this further, you can factor out any common factors in the numerator and the denominator. In this case, the numerator \(3x + 9\) can be factored as:

\[
3(x + 3)
\]

So the ratio becomes:

\[
\frac{3(x + 3)}{2x + 1}
\]

There are no common factors between the numerator and the denominator that can be canceled out, so this is the simplified form of the ratio.