If a point P (α, β, γ) satisfying (α β γ) (2, 10, 8; 9, 3, 8; 8, 4, 8) = (0, 0, 0) lies on the plane 2 x+4 y+3 z=5, then 6 α+9 β+7 γ is equal to:

If a point $\displaystyle \mathrm{P}(\alpha, \beta, \gamma)$ satisfying $$(\alpha \beta \gamma)\left(\begin{array}{lcl} 2 & 10 & 8 \\ 9 & 3 & 8 \\ 8 & 4 & 8 \end{array}\right)=\left(\begin{array}{lll} 0 & 0 & 0 \end{array}\right) $$ lies on the plane $\displaystyle 2 x+4 y+3 z=5$, then $\displaystyle 6 \alpha+9 \beta+7 \gamma$ is equal to :