Suppose y varies inversely with x. Write an equation for the inverse variation.

Question

anonymous · Answer

27. y=7 when x=3
29. y= -9 when x=2

kc_kennylau · Answer

If y varies inversely with x, xy should be a constant.

kc_kennylau · Answer

Therefore you can set xy=k and find k

mathmale · Answer

Another way to look at this case of "inverse proportion" would be to write the general formula 

y=k/x.  substituting the known values of x and y into this equation or Kenny's will give y ou the value of the constant of proportionality, k.

Finally, write y=k/x, substituting the value of k that y ou've just found.

anonymous · Answer

"Inverse variation" basically means that one variable is varying in a way that it's in the form:
$$y = \frac{k}{x}$$ 

So use that to find out k and write the equation you've found out, which should be your answer. e.g, one answer for such a question will look like this:

$$y = \frac{21}{x}$$