A particle moves along a straight line so that its displacement x metres from a fixed point O is given by x = t^3 - 6t^2 + 9t + 5, where t is measured in seconds.

What is the average velocity of the particle over the first 3 seconds?

What is the average speed of the particle over the first 3 seconds?

I got the average speed to be 8/3 m's (which i hope is correct) but not sure what to do about the velocity.

thanks