The trend equation = 150 + 12x + 0.01x2 has been developed for annual unit sales

Question:

The trend equation ŷ = 150 + 12x + 0.01x2 has been developed for annual unit sales of a filtering system component used by municipal water authorities. The years have been coded so that 2001 corresponds to x = 1. If the seasonal indexes for quarters I through IV are 85.0, 110.0, 125.0, and 80.0, respectively, estimate the unit sales for each quarter of 2015.