A direct variation function contains the points (2, 14) and (4, 28). Which equation represents the function?

A direct variation function contains the points (2, 14) and (4, 28). Which equation represents the function?
                                           28-14
Find the slope, m:    m = ------------ = 14/2 = 7
                                             4-2

Now find the equation of this line by using the point-slope equation:
y-28 = (7)(x-4)

You could change this to point-slope form:  y = 28 + 7(x-4), or y = 7x