Find the slope of a line between the points (5, 3) and (-2, -3).

Write an equation for the following problems:

A line with slope 1/3 and y-intercept 4

A line with slope 3 going through the point (1, -2)

A line going through the points (3, 2) and (-2, 4)

I am totally confused on how to find the answers to these types of problems. An explaination would be great. Thankies!