please calculate it manually (dont use excel)

3 4 5 642 623 The following table contains the demand from the last six weeks: Week 2 Demand 597 556 794 425 (a) Forecast the demand for week 7 using exponential smoothing with a=0.3.(3%) (b) Assume that the forecast for period I was 612, Forecast the demand for week 7 using exponential smoothing with a=0.3.(3%) (c) Write the formula for "exponential smoothing method and prove that, the more recent samples are weighted more heavily. (4%)