I DON'T UNDERSTAND MATH ANYMORE!!!!!!!!
One equation for this would be

We start by finding the slope between the two points:

A line parallel to this one will have the same slope. We will use point-slope form to write our equation:
If you're asking for the model for the second problem (I didn't see any unsolved), here it is!
Answer:
The graph above indicates that 1. Starts by drifting far away from the starting point (0,0), Then 2. Stays the same pace but still away from the starting point, finally 3. Starts coming toward the starting point and getting closer again.
Step-by-step explanation: