After declining between 1940 and 1980, the number of multigenerational American households has been increasing since 1980. The function h(x) = 0.012x2 - 0.583x + 35.727 can be used to estimate the number of multigenerational households in the United States, in millions, x years after 1940 (Source: Pew Research Center). Use this function for Exercise.
In what year were there 40 million multigenerational households?