how am I going to write an equation of the line about force and acceleration?

What formula should I use to fine the slope of an graph? What will be my unit of the slope?


What physical quantity does the slope represent?

If you have a graph of acceleration vs. force, then the slope will naturally be acceleration/force, or the amount that acceleration increases for a unit increase in force.

Now see if you can answer the rest of your questions.

what would an equation be that describes the relationship between force and acceleration?

Good old Newton and his second law of motion:

F = ma