For each function f and interval [a, b], a graph of f is given along with the secant line that passes though the graph of f at x = a and x = b.

  a.    Use the graph to make a conjecture about the value(s) of c satisfying the equation f ( b ) − f ( a ) b − a = f ′ ( c ) .

  b.    Verify your answer to part (a) by solving the equation f ( b ) − f ( a ) b − a = f ′ ( c ) for c.

7.     f ( x ) = x 5 16 ;   [ − 2 ,   2 ]