Question

How do you write an inverse variation equations given y=4 when x =7?

Answer 1

`xy=28`

Explanation:

An inverse variation is of the form:
`color(white)("XXX")xy=c` for some constant `c`.

For the equation `xy=28`

`color(white)("XXX")y=4`
`color(white)("XXX")rarr x=7`

If we multiply the value of `y` by `2` (for example)
`color(white)("XXX")y=8`
`color(white)("XXX")rarr x=7/2`
That is multiplying `y` by `2` results in the need to divide `x` by `2`;
which is the basic concept of inverse variation.