Answer
$\dfrac{3}{8x^{8}y^{7}}$
Work Step by Step
Using laws of exponents, the given expression simplifies to
\begin{align*}
&
\left(4x^6y^5\right)^{-2}(6x^4y^3)
\\\\&=
(4^{-2}x^{6(-2)}y^{5(-2)})(6x^4y^3)
\\\\&=
\dfrac{1}{4^2}(x^{-12}y^{-10})(6x^4y^3)
\\\\&=
\dfrac{1}{16}(x^{-12+4}y^{-10+3})(6)
\\\\&=
\dfrac{6}{16}(x^{-8}y^{-7})
\\\\&=
\dfrac{3}{8x^{8}y^{7}}
.\end{align*}
