can you help me with this? where e is the residuals. thanks

2.a. Suppose that the true linear regression model has the form Y = Bo + Pixi1 + $2xi2 + ci, 6: ~N(0, oz ), while we have misspecified it such that E[Y ] = Bo + Bix . Show that Elei] = $2(X12 + fxi1 + g), where e; is the residual left over after fitting the model, and f , g are functions of Xu and Xi2