medal for help with inverse variations please

Question

anonymous · Answer

which equation does not represent an inverse variation between x and z?

anonymous · Answer

$$z = \frac{ -15y }{x } OR x = \frac{ y }{ z } OR xz = 5y OR x = \frac{ -15z }{ y }$$

mathstudent55 · Answer

Inverse variation of x and z is:

$z = \dfrac{k}{x} $ or $x = \dfrac{k}{z} $

where k is a constant.

In other words, for you to have an inverse variation of x and z, you must have x on one side in the numerator and z on the other side in the denominator or vice-versa.

anonymous · Answer

thanks so much! the answer would be the 4th choice above, right

mathstudent55 · Answer

Correct.
Notice that in the third choice, if you divide both sides by x or by z, then one of them (x or z) will be in the numerator on one side and the other in the denominator on the other side, so choice 3 is inverse variation.

anonymous · Answer

yes thanks i saw that with choice three