# Alphabet

Algebra Level 3

\large \begin{align} abc - bcd + acd & = 0 \\ bcd - acd + abd & = 0 \end{align}

Let $$a,b,c$$ and $$d$$ satisfy the system of equations above and $$c$$ and $$d$$ are non-zero, find the value of $$a+b+c+d$$.

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