#### Answer

$\dfrac{b^{1/2}b^{3/4}}{-b^{1/4}}=-b$

#### Work Step by Step

$\dfrac{b^{1/2}b^{3/4}}{-b^{1/4}}$
Evaluate the product in the numerator:
$\dfrac{b^{1/2}b^{3/4}}{-b^{1/4}}=\dfrac{b^{1/2+3/4}}{-b^{1/4}}=\dfrac{b^{5/4}}{-b^{1/4}}=...$
Evaluate the division:
$...=-b^{5/4-1/4}=-b^{4/4}=-b$