Answer
$-x^1x^{-1}y^{-1} = -\frac{1}{y}$
Work Step by Step
By the formulas given on page eight and nine,
$-x^1y^{-1}x^{-1} = -x^{1+(-1)}y^{-1} = -x^{1-1} y^{-1} = -x^{0}y^{-1} = -x^0\frac{1}{y^1} = -\frac{x^0}{y}$.
By the definition of zero exponent, $x^0 = 1$. So
$-x^1x^{-1}y^{-1} = -\frac{x^0}{y} = -\frac{1}{y}$.
