A $2 \times 2$ square matrix $A$ satisfies the following conditions. (where $E$ is the identity matrix and $O$ is the zero matrix)\\
(A) $A ^ { 2 } + 2 A - E = O$\\
(B) $A \binom { 1 } { - 1 } = \binom { 3 } { 4 }$\\
Find the value of $x + y$ for real numbers $x , y$ satisfying $( A + 2 E ) \binom { x } { y } = \binom { 3 } { - 3 }$. [4 points]