Answer:
(31zy)/(13xz)
Explanation:
A reciprocal is a number that you can multiply the original number by and get a product of 1. To find the reciprocal of a fraction, flip it upside down, putting the numerator in the denominator, and the denominator in the numerator:

If we multiply this fraction by the other, we would end up simplifying it to 1 by cross multiplication.