$$\frac{x^{17} \cdot x^{27} \cdot z^{16} : x^{34}}{z^{64} : z^{35} \cdot x^{9} \cdot z^{17}} = \frac{x^{17+27-34}}{x^9} \cdot \frac{z^{16}}{z^{64-35+17}} = \frac{x^{10}}{x^9} \cdot \frac{z^{16}}{z^{46}} = x^{10-9} \cdot z^{16-46} = x^1 \cdot z^{-30} =$$
$$\frac{x}{z^{30}}$$