X 2 + 3y z if X=3,y= 6, and z=4

This week, conrad will work 1 3/4 times longer than last week. giovanni will work 1 1/3 times longer than last week. sally will work 2/3 the number of hours she worked last week. match each employee's name to the number of hours he or she will work this week

For how answer my question this will be the last question can you answer in math subject

What is the average rate of change for this function for the interval from x=2 to x=4 ?