[tex]\it 1400:10-120:(x+y) =0\cdot6+4(2+3\cdot9) \Leftrightarrow
\\\;\\
\Leftrightarrow 140-120:(x+y) = 4\cdot29|_{:4} \Leftrightarrow 35-30:(x+y) =29 \Leftrightarrow
\\\;\\
\Leftrightarrow 35-29=30:(x+y) \Leftrightarrow 30:(x+y) = 6 |_{:6} \Leftrightarrow 5:(x+y) =1
\\\;\\\Leftrightarrow x+y=5 = 0+1=1+4=2+3=3+2=4+1=5+0[/tex]
[tex]\it (x,\ y) \in \{(0,\ 5), (1,\ 4), (2,\ 3), (3,\ 2), (4,\ 1), (5,\ 0)\}[/tex]