The following equation summarizes the trend portion of quarterly sales of condominiums over a long cycle. Sales also exhibit seasonal variations. Using the information given, make a forecast of sales for each quarter of next year (not this year), and the first quarter of the year following that.

Ft = 40 - 6.5t + 2t2

where

Ft = Unit Sales t = 0 at the first quarter of last year

Quarter Relative

1 1.1 2 1.0 3 .6 4 1.3