Yes, these both are direct relationships and can be written like
![y = kx](https://img.qammunity.org/2019/formulas/mathematics/college/1irueestzcfe1jy6nsxceq3bgce3a8o4zs.png)
, where k is the constant of variation.
For the first equation, k = 10. For the second equation, k = -4/3. You find it by rearranging the equation into the form
![y=kx](https://img.qammunity.org/2019/formulas/mathematics/middle-school/osmso2dhwzjg9noqmcagd0wrvsv42x2mtn.png)
, and you use the coefficient of x for k.