## Algebra: A Combined Approach (4th Edition)

$-\dfrac{5a^{2}b}{30a^{2}b^{2}}\cdot b^{3}=-\dfrac{b^{2}}{6}$
$-\dfrac{5a^{2}b}{30a^{2}b^{2}}\cdot b^{3}$ Multiply both expressions and simplify by removing repeated factors in the numerator and the denominator: $-\dfrac{5a^{2}b}{30a^{2}b^{2}}\cdot b^{3}=-\dfrac{5a^{2}b^{4}}{30a^{2}b^{2}}=-\dfrac{5b^{2}}{30}=-\dfrac{b^{2}}{6}$