3d Geometry

Let \(\mathrm{P}\) be the plane passing through the line

\(\frac{x-1}{1}=\frac{y-2}{-3}=\frac{z+5}{7}\) and the point \((2,4,-3)\).

If the image of the point \((-1,3,4)\) in the plane P

is \((\alpha, \beta, \gamma)\) then \(\alpha+\beta+\gamma\) is equal to :