Answer: 0.5
Step-by-step explanation:
Answer:
6m+7.5
Step-by-step explanation:
the arithmetic mean is the average of two numbers
it is given that a is average of 6m and 10
so 
b is the average of 4m and 4
so 
c is the average of 14m and 16
so 
now the average of a ,b and c is given by

The answer I got is (2x^2+x-15)