IN the given position-time graph of a non-uniform motion what will be the average velocity between ${{x}_{1}}$ and ${{x}_{2}}$?

In the given position-time graph of a non-uniform motion what will be the average velocity between {{x}_{1}} and {{x}_{2}} ?

Average velocity is the slope of the line {{x}_{1}}, {{x}_{2}} , i.e.,