How do you determine whether the equation -12x=6y represents direct variation. If it does, how do you find the constant of variation?

2 Answers
Jan 2, 2018

If an expression can be re-formatted into the form:
color(white)("XXX")y=color(blue)c * x for some constant color(blue)c then it is a direct variation.

Explanation:

In this case -12x=6y
can be written as
color(white)("XXX")y=color(blue)(""(-2))x
and therefore it is a direct variation.

Jan 2, 2018

k=-2

Explanation:

"the equation for direct variation is of the form"

•color(white)(x)y=kxlarrcolor(blue)"k is the constant of variation"

6y=-12x" can be expressed as"

"divide both sides by 6"

y=-2xlarrcolor(blue)"direct variation equation"

"with "k=-2