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?

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Answer 1 · 2016-01-21T11:26:41

$y = 3/5 * x$

$y prop x$ 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 · 2016-01-21T11:43:17

$y=9/15x$

$y$ 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:

$y=9/15x$