Find the distance between A and B

If given an equation of a line such as -1/2x+6 how would you create an equation of a line parallel and perpendicula to this line that goes through another point such as (4,10)

I’m still confused on how to work the percentages

In stepmber, daniel and justin opened a business. during their first three months of business, their average monthly profit was $51. if during their first month, they lost $29, and during their second month, they gained $115, what was their profit or loss for their third plzzz i will give you 299 points