Please show work so I can know how this should be computed, thank you!

Sales of Volkswagen's popular Beetle have grown steadily at auto dealerships in Nevada during the past 5 years (see table below). Using exponential smoothing with a smoothing constant (a) of 0.30 and a starting forecast of 415.00, the following sales forecast has been developed: Year Sales 2005 2006 2007 2008 455 510 516 563 585 Forecasted Sales 415.00 427.00 451.90 471.13 498.69 2009 The MAD for a forecast developed using exponential smoothing with a = 0.30 is sales (round your response to two decimal places) Forecasted sales for years 2006 through 2010 using exponential smoothing with a = 0.60 and a starting forecast of 415.00 are (round your responses to two decimal places): 2005 2006 2007 2008 2009 2010 Year Forecasted Sales 415.00 The MAD for a forecast developed using exponential smoothing with a = 0.60 is sales (round your response to two decimal places)