Hello. I don’t understand this. How do I find the slope of the line?

The equation for slope is [tex]\frac{y_2-y_1}{x_2-x_1}[/tex]. For example, here are the steps for #4:
[tex]\frac{y_2-y_1}{x_2-x_1}[/tex]
[tex]\frac{0-4}{0-1}[/tex]
[tex]\frac{-4}{-1}[/tex]
Another name for slope is [tex]\frac{rise}{run}[/tex].