Question

In the direct variation model, y=.5x, if y=10, how do you give the value of x?

Answer 1

`x=20`

Explanation:

If `y = (0.5)x` and `y = 10`
then
`color(white)("XXXX")` `10 = (0.5)x`
and, multiplying each side be `2`, we get
`color(white)("XXXX")` `20 =(1.0)x`
or
`color(white)("XXXX")` `x = 20`

We can verify this by taking the original direct variation model:
`color(white)("XXXX")` `y = .5x`
and substituting `20` for `x`
`color(white)("XXXX")` `y = .5xx20 = 10`
as given as a condition.