statistics help please

Fig. 1 is the ACF/PACE of the time series Y(t), t=1,100. The p-value for the associated ADF test is 0.42. Fig. 2 is the ACF/PACF after first differencing Y(t), i.e. the ACF/PACE of (1-B)Y(t). The p-value of the associated ADF test is 0.009. 0.8 0.8 Partial ACF ACF 0.0 0.0 TTTT 0.0 0.5 1.0 1.5 2.0 0.5 1.0 1.5 2.0 Lag Lag Fig. 1: ACF and PACF of Y(t) LAG LAG Fig. 2: ACF and PACE of (1-B) Y(t) 8) Write the forecasting rule for Y(100+s), s=1, 2,., implied by the model you propose