A forecasting equation developed by Least squares is of the from y $=800+145$x $($July $1,1998=0,$ x $=$ year code, y $=$ Annual sales$)($a$)$ Forecast the annual sales rate for year $1998$ and also for $1$ year later.$($b$)$ Change the time $($x$)$ scale to month and write the equations.$($c$)$ Change the y scale to monthly forecast monthly and forecast the sales rate at July $1,1998$ and also at $1$ Year later?