Question

Given that y varies directly with x, and x = 28, y = -4, how do you write a direct variation equation that relates x and y?

Answer 1

`y = (-x)/7`

Explanation:

Write a direct proportion, turn it into an equation, find the constant and you will have an equation connecting `x and y`.

`y prop x " " rArr y = kx " multiply by a constant"`

`k = y/x " rArr k = -4/28 = -1/7`

`:. y = (-1x)/7 " or " y = (-x)/7`