Question

(Calculator Needed) The median size of a new single family house (in square
feet) built in the U.S. between 1987 and 2001 can be modeled as
h(x) = 0.359x3 -15.198x2 + 221.738x + 826.514;
where x is the number of years since 1980.
Find all possible inflection points of h from 1987 to 2001 and determine whether it is actually
an inflection point.