3 . The production of housing has the following form:
H = number of housing units = 4(L + 10)1/2 + 80 (M + 3)3/4, where L is land and M is
materials. One unit of L costs 100 and 1 unit of M costs 12.
Find the cheapest ways to produce 1000 housing units, 2000 housing units, and 5000
housing units.