Negative exponent

$\large{\left(\dfrac{9^{-3}}{3^{-5}}\right)^{-2}=x}$

$\large\left(\dfrac{3^{2.(-3)}}{3^{-5}}\right)^{-2}=x$

$\large\left(\dfrac{3^{-6}}{3^{-5}}\right)^{-2}=x$

$\large\left(3^{-6+5}\right)^{-2}=x$

$\large\left(3^{-1}\right)^{-2}=x$

$\large3^{2}=x$

$\large\boxed{9}=x$

$\left(\dfrac{9^{-3}}{3^{-5}}\right)^{-2}=\left(\dfrac{3^5}{9^3}\right)^{-2}=\left(\dfrac{3\cdot 3\cdot 3 \cdot 3 \cdot 3}{9\cdot 9 \cdot 9}\right)^{-2}=\left(\dfrac{9\cdot 9\cdot 3}{9\cdot 9 \cdot 9}\right)^{-2}=\left(\dfrac{1}{3}\right)^{-2}=\dfrac{1}{\left(\dfrac{1}{3}\right)^2}=\dfrac{1}{\dfrac{1}{9}}=1 \cdot \dfrac{9}{1}=\boxed{9}$

${\left(\dfrac{9^{-3}}{3^{-5}}\right)^{-2} = x}$

$\Rightarrow \left(\dfrac{1}{3}\right)^{-2} = x$

$\Rightarrow \left(\dfrac{3}{1} \right)^2 = x$

$\Rightarrow 9 =x$

Hence $x = \boxed{9}$