Question

Question #fea28

Answer 1

`y-5=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`, `y!=0` so the equation is not direct variation.
`(0)-5=2(0)`
`"-"5=0`
`"false"`