Answer: The second option and the third option are true.
Explanation:
The formula of the line in slope-intercept form is:
![y=mx+b](https://img.qammunity.org/2020/formulas/mathematics/high-school/8nudzfk4b5l0arb9iixag2w8am6zn99zlr.png)
Where m is the slope and b is the y-intercept.
By definition, the y-intercept in a direct variation is 0.
Therefore, substituting
and
into the equation, you obtain:
![y=-3x+0](https://img.qammunity.org/2020/formulas/mathematics/high-school/38bjj340ivtp8l8dsezxfpfj70syugl5zb.png)
Then, the equation is:
![y=-3x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/vfgukt2ocswdz4t17yteuj6cqaccscmeno.png)
As this is a line, it is a linear function.
Therefore, the second option and the third option are true.