Please help me solve this

Find the nonpermissible replacement for binthis expression.b2/5b +5

Atotal of 766 tickets were sold for the school play. they were either adult tickets or student tickets. there were 66 more student tickets sold than adult tickets. how many adult tickets were sold?

Describe how to determine the average rate of change between x = 4 and x = 6 for the function f(x) = 2x^3 + 4. include the average rate of change in your answer.