Put numbers up and down the X and Y axis showing what the graph values are. (Ex: see picture ) make sure you do it accurately based on what the slope will look like.
to find the slope for the first one, use the formula 
(It's the slope formula)
so... 
then plug in... 
this line has a slope of 0
As for the miles problem, to find mph, the miles have to be at 1.
so... 
therefore, he drove 60.5 mph
48 fluid ounces. There's 8 oz in one cup:)
Can you put more information into this question