what exactly did you not understand about this?
You have to do some of the thinking here, otherwise, you are mostly answer grazing.
http://www.jiskha.com/display.cgi?id=1309223857
The graph of f(x)=x^3-3x^2-24x+1 is concave up when x<-2, x<4, x>-6, or x>1?
1 answer