For this case, what you should know is that the equations that represent an inverse variation are those that could not form a straight line, for example.
We have then:
Equation 1:
pv = 13
Rewriting:
p = 13 / v
P and v are represent an inverse variation.
Equation 2:
z = (2 / x)
z and x are represent an inverse variation.
Answer:
equations represented inverse variation are:
pv = 13
z = (2 / x)