Answer it by using Python.

$8\mathrm{.}6$ Linear functions. For each description of $y$ below, express it as $y=Ax$ for some $A.($You

should specify $A.)$

$($a$)y_i$ is the difference between $x_i$ and the average of $x_1,$dots,$x_{i-1}.($We take $y_1=x_1.)$

$($b$)y_i$ is the difference between $x_i$ and the average value of all other $x_j$ s$,$ i$.$e$.,$ the average

of $x_1,$dots,$x_{i-1},x_{i+1},$dots,$x_n$