There's a stationary point of inflection at (0, -1).
There's a minimum turning at . If you want to use the cubic formula to solve for x (at least it's a depressed cubic so that's a start) be my guest. There's no simple way of getting the exact value of x.
Does the book have an answer at the back?
Then you should ask your instructor for solutions or, at least, answers.
If you want an exact value for the x-coordinate of the minimum turning point, solve the cubic equation by following the process given here: Cubic Formula -- from Wolfram MathWorld
Good luck substituting this exact value into y = f(x) to get the y-coordinate.
Thanks a lot for giving for time...
actually I am studying part time through distant learning and there is no instructor to guide so i thought anyone here can help. hence i posted two questions which only i was not able to solve in last 4 question papers. one is this question and another is
http://www.mathhelpforum.com/math-he...-equation.html
regards
Kr.
PS: I also tried formula given here http://en.wikipedia.org/wiki/Cubic_equation