How do i calculate average velocity

Average velocity has two parts:  Its magnitude (size) and its direction.

Its magnitude is

(straight-line distance between start-point and end-point, regardless of the route that's actually followed from start to finish) divided by (time taken to travel from start to finish).

Its direction is

(direction from start-point to end-point)

Notice that straight from this definition, the average velocity of going around a full circle is zero, no matter how fast you traveled.  That's because the size of the  average velocity is calculated from the straight-line distance from start-point to end-point, and that's zero if you finish at the same point you started from.

step-by-step explanation:

we are given

we have to simplify it

firstly, we will factor it

now, we can cancel like terms

now, we can combine it

so, we get