Is this an error in Oppenheim and Schafer's Discrete-Time Signal Processing (3rd edt)?
$$\begin{align}
Y(z) &amp;= E(z) + \frac{1}{1-z^{-1}}(X(z) - z^{-1} Y(z)) \\
 &amp;= E(z) + \frac{1}{1-z^{-1}}X(z) - \frac{z^{-1}}{1-z^{-1}} Y(z) \\
\\
Y(z) + \frac{z^{-1}}{1-z^{-1}} Y(z) &amp;= E(z) + \frac{1}{1-z^{-1}}X(z) \\
\left(1 + \frac{z^{-1}}{1-z^{-1}}\right) Y(z) &amp;= E(z) + \frac{1}{1-z^{-1}}X(z) \\
 \frac{1}{1-z^{-1}} Y(z) &amp;= E(z) + \frac{1}{1-z^{-1}}X(z) \\
\end{align} $$
this results in:
$$ Y(z) = (1-z^{-1})E(z) + X(z) $$