Just find two places where the line passes through a point. For example for number one, it would be (5,4) and (2,3). Then, count how many whole units are between them and then you have slope (rise (up and down) divided by run (side to side)
So, going back to number one, your answer would be 1/3 because you go up one block and over three blocks to get from (5,4) to (2,3). Also, if you look at the line and it is an incline, then it is positive (like number one). But, if the line is a decline, then your slope would be negative (like number three).
I know I didn't give you the answers, but hopefully you understand it better!
