Iforgot how to indicate whether the lines are parallel perpendicular or neither

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

What is the slope of the line (-7,2) (4,6)

I’m really confused and need to learn this