Connecting Averages Hayden

Basically on the first question, you first name the squares, x , y , z and you can rearrange them into  a system of three equations ( basically a simulataneous equation). For example, you make z the subject and subsitute everything into the other equations since z should be on its own. Then you do that again and finally get one of the squares. Using that you can find the mean of the other squares by adding the surrounding numbers including the letter and times the square you just got by 4 to make the total of the surrounding numbers. Then you do that for the rest and get all of the squares.