ta có $25 .pt(1) +50.pt(2)$ ta đc$225x^{2}+150xy+25y^{2}+150x+50y-119=0$
$\Leftrightarrow (15x+5y)^{2}+10(15x+5y)-119=0$
$\Leftrightarrow 15x+5y=7$ or $15x+5y=-17$
+) $15x+5y=7 \Leftrightarrow (x;y)=(\frac{11}{25};\frac{2}{25});(\frac{2}{5};\frac{1}{5})$
+) $15x+5y=-17 \Rightarrow VNo$