=>2x+xy=9
=>x(y+2)=9
\(\Leftrightarrow\left(x;y+2\right)\in\left\{\left(1;9\right);\left(9;1\right);\left(-1;-9\right);\left(-9;-1\right);\left(3;3\right);\left(-3;-3\right)\right\}\)
=>\(\left(x,y\right)\in\left\{\left(1;7\right);\left(9;-1\right);\left(-1;-11\right);\left(-9;-3\right);\left(3;1\right);\left(-3;-5\right)\right\}\)