Please help with last step. Show all steps to solving.

The monthly sales for Yazici Batteries, Inc., were as follows: This exercise contains only parts b and c. b) The forecast for the next month (Jan) using the naive method =23 sales (round your response to a whole number). The forecast for the next period (Jan) using a 3-month moving average approach = sales (round your response to two decimal places). The forecast for the next period (Jan) using a 6-month weighted average with weights of 0.10,0.10,0.10,0.20,0.20, and 0.30 , where the heaviest weights are applied to the most recent month = 21.0 sales (round your response to one decimal place). Using exponential smoothing with =0.40 and a September forecast of 18.00 , the forecast for the next period (Jan)=21.60 sales (round your response to two decimal places). Using a method of trend projection, the forecast for the next month (Jan) = sales (round your response to two decimal places)