Use what you learned back in algebra. For f(x) to have a local max or min, there has to be a critical point, right? So you'd have to be able to find a zero for the derivative. This derivative is a quadratic in x50
:. . . . .
Set the right-hand side above equal to zero, and apply the Quadratic Formula to find the solution value for x50
. Can you then find a real value for x (being an even-index root of x50