Question

Is `5y=-4x` a direct variation equation and if so, what is the constant of variation?

Answer 1

The reqd. constant of variation is `k=-4/5.`

Explanation:

Observe that if `y` varies directly as `x`, i.e., `yprop x`, then using `k!=0` as constant of variation, the eqn. is written `y=kx.` ...(1)

In our case, we are given that, `5y=-4x,` i.e.,
`y=(-4/5)x.`... (2)

comparing (1) & (2), the reqd. constant of variation is `k=-4/5.`