I know that:
W = W transpose
is symmetric,
but how would I go about this question, how would I get started?
Any help is appreciated!
$\displaystyle (W-I)^T = 2W \ \ (\star)$
Using the property that: $\displaystyle (A \pm B)^T = A^T \pm B^T$
we have that: $\displaystyle W^T - I = 2W \ \Leftrightarrow \ {\color{blue}I = W^T - 2W}$
Now take the transpose of both sides of $\displaystyle (\star)$ and solve for $\displaystyle I$. Compare this expression with what we have in blue and you should get what you want.