Question #fea28

1 Answer
Apr 20, 2017

y5=2x is not an example of direct variation.

Explanation:

Direct variation means that one variable is equal to a constant times another variable. That is, y=kx. Rearranging the equation above, we get y=2x+5 which is obviously not in the form y=kx, but it can be proven a bit more convincingly that this is not direct variation by noting that whenever one variable varies directly as another, when one is zero so is the other. That is, if y=kx then when x=0, y=0. This is intuitively true because any k times 0 will be 0. Plugging x=0 and y=0 into the equation above we get a contradiction, thus when x=0, y0 so the equation is not direct variation.
(0)5=2(0)
-5=0
false