Answer
$\frac{1}{x^{9}}$
Work Step by Step
We are given the expression $\frac{x^{11}}{x^{20}}$. We can use the quotient rule to simplify this expression.
$\frac{x^{11}}{x^{20}}=x^{11-20}=x^{-9}$
We know that $a^{-n}=\frac{1}{a^{n}}$ (where a is a nonzero real number and n is a positive integer).
Therefore, $x^{-9}=\frac{1}{x^{9}}$