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?

2 Answers

# 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]

Jan 21, 2016

#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#