# Think of the number 11

Algebra Level 4

Find $$x,y,z$$ satisfying the equations
$\large{ \begin{cases} (x+y)(x+y+z)=66 \\ (y+z)(x+y+z)=99 \\ (z+x)(x+y+z)=77 \end{cases}}$

Submit your answer as the sum of all possible values of $$(x+y+z).$$

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