In the equation x=−3y, what is the unit rate?

The unit rate is -1/3.

In direct variation, y varies directly to x by a constant ratio k.

Its equation looks like this: y = kx ; where k stands for the constant ratio.

In the above equation. x = -3y, it should be converted to the proper equation. both sides must be transferred and its accompanying sign must be changed.

3y = -x
3y/3 = -x/3
y = (-1/3)x
where: y is the total value; -1/3 is the unit rate; and x is the number of units