Como hacer una derivada?

Can some one me with these questions

Can somebody 1. what is the formula for finding the vertical distance between two points on a coordinate plane?

Axel follows these steps to divide 40 by 9: start with 40. 1. divide by 9 and write down the remainder. 2. write a zero after the remainder. 3. repeat steps 1 and 2 until you have a remainder of zero. examine his work, and then complete the statements below.