I need step by step

If u use some important theorem, please write it down briefly

If u answer my question correctly, I'll rate u immediately

Don't just copy and paste others answer

and if u use handwriting, please make it easy to read

thank you

The joint denstay of A and B is given by - b fla , b ) = e ocach, ocbcoo Compute E[A' | B = bJ and Cov LA. B )