Im confused can someone please explain how to do this

First rewrite the mixed number as an improper fraction:

-1 1/14 = -15/14

Now you have :

-3/7 / -15/14

When dividing by a fraction, flip the second fraction over and change divide to multiply:

-3/7 x -14/15

Now multiply top by top and bottom by bottom:

(-3 x -14) / ( 7 x 15) = 42/105

Simplify by diving each number by 21 to get the final answer :

2/5