The average rate of change of function describes the average rate at which y-value ( or f(x)) is changing with respect to changing x-value. The average rate of change= In this exaple is x1=4 and x2=7 and we will find y1 and y2: y1=3(4-3)²+4=3*1+4=7 y2=3(7-3)²+4=3*16+4=48+4=52 Finally: Answer: The average rate of change for f(x) from x=4 to x=7 is 15.