If y varies directly with x, and if y = 2/3 when x = 1/4, how do you find the direct variation equation?

1 Answer
Alan P.
Apr 6, 2016

3y=8x

Explanation:

If y varies directly with x then
color(white)("XXX")y=c*x for some constant of variation c

If (x,y)=(1/4,2/3) is a solution to this equation, then
color(white)("XXX")2/3 = c*1/4

color(white)("XXX")rarr c=2/3 *4/1 = 8/3

So
color(white)("XXX")y=8/3x
or (clearing the fraction)
color(white)("XXX")3y=8x

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