Multiply the polynomials (3x - 1) (2x + 4).

To multiply the polynomials \( (3x - 1)(2x + 4) \), we can use the distributive property, often referred to as the FOIL method for binomials, which stands for First, Outside, Inside, Last.

1. **First terms**: \( 3x \cdot 2x = 6x^2 \)
2. **Outside terms**: \( 3x \cdot 4 = 12x \)
3. **Inside terms**: \( -1 \cdot 2x = -2x \)
4. **Last terms**: \( -1 \cdot 4 = -4 \)

Now, combine all these results:

\[
6x^2 + 12x - 2x - 4
\]

Combining the like terms (\( 12x - 2x \)) gives:

\[
6x^2 + 10x - 4
\]

So the product of the polynomials \( (3x - 1)(2x + 4) \) is:

\[
6x^2 + 10x - 4
\]

Filling in your blanks, we have:

\[
\_x^2 + \_x + \_
\]

This translates to:

\[
6x^2 + 10x - 4
\]

Thus, the completed expression is:

6, 10, -4