Design Project via State Space
There is an unnamed node in the flow diagram between \$z_2\$ and \$z_1\$. Call it \$k\$. The equation for \$k\$ can be written as:

\[
k = z_2 - 5 z_1
\]

Then the equation for y becomes:

\[
y = k + 4 z_1 = (z_2 - 5 z_1) + 4 z_1 = -z_1 + z_2 = [-1\quad 1\quad 0]\;\textbf{z}
\]