Question

How do you know when the line is moving up or down when finding the slope from a graph

Answer 1

We can relate the slope with the direction of the line by looking at the sign of the slope.

If the slope m is m>0, then the line increases its value when x increases: the line moves up.

If the slope m is m<0, then the line decreases when x increases: the line moves down.

The case when m=0 is the horizontal line, where the line stays at a constant value for all values of x.