Based on the information in the following, use the Exponential Smoothing method to forecast the demand in period 13 (January) when a=0.2

PERIOD	MONTH	Demand	Forecast ( a=0.2)
1	Jan	110
2	Feb	70	110.00
3	Mar	80	102.00
4	Apr	150	Answer
5	May	130	Answer
6	June	140	Answer
7	July	90	Answer
8	August	120	Answer
9	September	130	Answer
10	October	70	Answer
11	November	160	Answer
12	December	170	Answer
13	January

Explain how to solve plz