Click on the points that appear to be maximum or minimum values and Desmos will tell you the coordinates of the point.
2
Notice that the polynomial doesn't actually have a maximum or minimum value, because it keeps going both up and down forever. That's why we call these "relative" maximum and minimum values.
3
Expression 4: "x" cubed minus 3 "x" squared minus 24 "x" plus 5 Has graph. To audio trace, press ALT+T.x3−3x2−24x+5