How do you find the slope of a line? (4 , 3) and (8 , 5)

also how do you determine if the slope is zero, positive, zero or undefined?

Zero is undefined and X would equal 4 and Y would equal 2 which when you divide the two you get 1/2

To find the slope of the line from two points, you need to substitute your values in your coordinates into a formula.  The formula is called the Point to Slope Formula, at least that is what I call it.  The formula looks like this.

y2 - y1/x2 - x1

In more detail, y2 refers to the y coordinate of the second coordinate pair, which is 5.  y1 refers to the y coordinate of the first coordinate pair, which is 3.  Determine these values for each of the four coordinates and then substitute them into the formula.  It will then look like this:

5 - 3/8 - 4

Then you simply subtract and divide.

2/4
=
1/2

The slope of your line is 1/2.

Hope this helps! :)