1. Click cell C9, enter the formula =INDEX(LINEST (sales Y, time series X, TRUE, TRUE), 1, 1) to calculate the value of a in formula Y = A * XB.
2. Click cell D9, enter the formula =INDEX(LINEST (sales y, time series X, TRUE, TRUE), 1, 2) and calculate the value of b in the formula y = a * XB.
3. Enter the formula =INDEX(LINEST (sales y, time series X, TRUE, TRUE), 3, 1) in cell E9 to calculate the value of R 2.
4. Click cell F9 and enter the formula =C9*5D9 to calculate the estimated product sales in 2022.