ANSWER
[tex]\frac{ {x - }^{2} - 16}{4 {x}^{3} + 6 {x}^{2} } [/tex]
EXPLANATION
The given rational expression is
[tex] \frac{x - 4}{2 {x}^{2} } \div \frac{2x + 3}{x + 4} [/tex]
We multiply by the reciprocal of the second function to get:
[tex]\frac{x - 4}{2 {x}^{2} } \times \frac{x + 4}{2x + 3} [/tex]
The product of the numerators are difference of two squares:
When we multiply out and expand we get:
[tex]\frac{ {x - }^{2} - 16}{4 {x}^{3} + 6 {x}^{2} } [/tex]