Question

What does ΔX mean in this equation?

Answer 1

the triangle before the x means "change in x" which is: (finalx - initialx)

So if the interval is 1 sec to 3 sec, change in t would be 3-1=2 sec. The corresponding x-values are 30-10=20

change in x / change in t = (30-10)/(3-1) = 10 m/s