## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$\dfrac{10}{a^{6}b^{2}}$
Using the laws of exponents, the given expression, $(5a^{-2}b^{-3})(2a^{-4}b)$, is equivalent to \begin{array}{l} 5(2)a^{-2+(-4)}b^{-3+1} \\\\= 10a^{-6}b^{-2} \\\\= \dfrac{10}{a^{6}b^{2}} .\end{array}