Hi there!
The answer is:
[tex]8x(2x - 3)[/tex]
We can see this, by writing the terms as multipliers.
[tex]16x {}^{2} = 8 \times 2 \times x \times x[/tex]
[tex]24x = 8 \times 3 \times x[/tex]
The terms 8 and x are in common and therefore, we can bring those outside the parentheses.