Question

Given that y varies directly with x, and x = 15, y = 9, how do you write a direct variation equation that relates x and y?

Answer 1

`y = 3/5 * x`

Explanation:

`y prop x` So `y = k* x` where k is constant
Here `k = 9/15` So `y = 9/15 * x`
which simplifies to
`y = 3/5 * x` [Answer]

Answer 2

`y=9/15x`

Explanation:

`y` varies directly with `x`

So `ycolor(white)(.) alphacolor(white)(.) x`

`y=kx`.................(1)

Where `k` is some constant

Given that `y:x->9:15`

Substitute given value of `y,x` into equation (1) giving:

`y=kx->9=15k`

Divide both sides by 15 giving:

`k=9/15`

So the direct variation equation is:

`y=9/15x`