loss matrix for B

A$\displaystyle \left [ \begin{matrix} 7 & 9 & 8 & 10 \\ 12 & 1 & -2 & -3 \\ 5 & 5 & 6 & 9 \\10 & 6 & -3 & -4 \end{matrix} \right]$

Using dominance property i got a 3x2 matrix as

$\displaystyle \left[ \begin{matrix} 7 & 8 & 10 \\ 12 & -2 & -3 \end{matrix} \right]$

and my graph with equations

$\displaystyle 7x_1 + 12x_2 \geqslant V$
$\displaystyle 8x_1 - 2x_2 \geqslant V$
$\displaystyle 10x_1 - 3x_2 \geqslant V$

Game Theory - graphical method-imag0692.jpg

so the highest intersection point 2x2 matrix is with 1st and 2nd columns from the 3x2 matrix

$\displaystyle \left[ \begin{matrix} 7 & 8 \\ 12 & -2 \end{matrix} \right]$ is this correct or is there something wrong in my graph.