Answer:
both rates of change equal the slope of the line (3/4)
Step-by-step explanation:
Part a)
We calculate the rate of change using the formula:

for the first interval [0,6], we calculate the y-values at x=0 and x=6;
at x=0 : 
at x=6 : 
therefore, the rate of change in this interval is: 
For the second interval [-4,4], we calculate the y-values at x=-4 and x=4;
at x=-4 : 
at x=4 : 
therefore, the rate of change in this interval is: 
Part b):
Notice that both rates of change equal the value of the slope of the linear function (3/2)