## How do you derive formulas?

So in my physics worksheet paper there was a maths related question
The teacher was in a rush and didn't really explain much and asked to derive this formula
And I was so clueless (yea the teacher isn't good)

Here is the question

The magnetic force F that acts on a current carrying conductor in a magnetic field is
F=BIl

Where i is the current , l is the length of the conductor
The unit for magnetic flux density B is the Tesla

Express the Tesla in base units