Direct variation and slope intercept form

by Cindy
(Ocoee, Florida, US)

What are some examples of slope intercept form representing direct variation?


Answered by Karin on

Hi Cindy,

Thank you for contributing to Direct variation is when two variable quantities have a constant ratio. The formula for direct variation is:
y = kx where k is the constant of variation.

You asked for an example in slope intercept form. As you can see, direct variation is set up in slope intercept form.

y = kx is very similar to y = mx. With direct variation, the y-intercept is 0, so you won't have the "+b" portion of slope intercept form. The constant of variation (k) is very similar to the slope in slope intercept form.

Some examples of equations that represent direct variation are:

y = 5x

y = 1/2x

y = .3x

As you can see, these are all set up in slope intercept form (with a y-intercept of 0).

These equations are called "direct variation" because y varies directly with x. If x increases, then y increases as well. If x decreases, then y decreases.

I hope this helps.


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