He was walking backwards.
His endpoint was in the negative x-direction AND in the negative y-direction, compared to his starting point.
It means he was feeling bad during the walk home.
He walked further in the y direction than the x.
The y direction was "up" so its a large number.
He walked faster in the y direction than he did the x direction.
Going to school is negative.
They walked in the negative y direction.
They walked slower in the y direction.
Here's an interesting quiz for you.