Answer
$= \frac{5b}{4} - 1 - \frac{3}{2b}$
Work Step by Step
$\frac{5b^{3}-4b^{2}-6b}{4b^{2}}$
$= \frac{b(5b^{2}-4b-6)}{b(4b)}$
$= \frac{5b^{2}-4b-6}{4b}$
$= \frac{5b^{2}}{4b} - \frac{4b}{4b} - \frac{6}{4b}$
$= \frac{5b}{4} - 1 - \frac{3}{2b}$