Answer: The answer is 
Step-by-step explanation: Let the Pairs of given points be
(i) A(-1,12) and B(6,26),
(ii) C(-1,-9) and D(3,3),
(iii) E(12,6) and F(11,13).
Now, the rate of change for pair (i) is given by

Rate of change for pair (ii) is given by

Rate of change for pair (iii) is given by

Therefore, the average rate of change for all the sets is

Thus, the answer is 