Question

A direct variation function contains the points (-8,-6) and (12,9). Which equation represents the function?

Answer 1

In this case, the work you need to do is exactly the same as you would to find the slope-intercept form of the equation of a straight line. First, find the constant of proportionality, k, in exactly the same way in which you'd find the slope, m.

Then write out your relationship in the form y = k x, where k is the constant of proportionality (slope) that you've just found.