Of the following equations is an example of inverse variation between the variables x and y?
a. y=5x
b. y=5/x
c. y=x+5
d. y=x/5

Inverse variation takes the form xy=k or if you prefer, y=k/x

Inverse variation simply means that as the independent variable increases/decreases the dependent variable does the opposite.

(Direct variation takes the form y=kx  the dependent variable increases/decreases just as the independent variable does.)

So B. is the one of the form y=k/x meaning that it has an inverse relationship.