a turtle is traveling at a speed of 2.5 mph. a hungry vulture is been chasing the turtle and the turtles speed increases at a constant rate of 1 mile per hour every second

If variable y represents the speed of the turtle, and x the time, then, for the given situation you can write the following equation:
y = 2.5 + 1x
which means that from a speed of 2.5mph the turtle has increased 1x miles per hour its speed after x seconds.
A plot of the graph is shown below: