please solve and show steps with detail$(20$ points$)$ An electric company has the following average monthly price for a customer

the past $10$ months.

Compute the exponentially smoothed forecast with $=0\mathrm{.}40$

The adjusted exponentially smoothed forecast with $=0\mathrm{.}40$ and $=0\mathrm{.}30$

The linear trend line forecast.

Compare the accuracy of the three forecasts using cumulative error and MAD,

and indicate which forecast appears to be most accurate.