Luke is swimming in still water at a constant speed of 3 meters/second. if you graph this relationship with time along the x-axis and distance along the y-axis, the slope of the line representing this relationship is? a point on this line that corresponds to the the distance luke swam in 45 seconds is?

The first thing you should know is that distance is defined as the product of speed over time.
 We have then:
 d = v * t
 Then, we know that:
 v = 3 m / s
 therefore, the slope of the line is:
 3m / s
 For t = 45 seconds we have:
 d = v * t
 d = (3) * (45).
 d = 135 m
 The point is:
 (45, 135)
 
 The slope of the line representing this relationship is:
 3m / s
 A point on this line that corresponds to the distance Luke swam in 45
seconds is:
 (45, 135)