Đáp án:
$\left \{ \matrix{{(2x+3)(3y+2)=6xy+9} \hfill\cr {(5-x)(7-y)=xy+19}} \right. \\⇔\left \{\matrix {{6xy+4x+9y+6=6xy+9} \hfilll\cr {35-5y-7x+xy=xy+19}} \right. \\⇔\left \{\matrix {{6xy+4x+9y-6xy=9-6} \hfill\cr {-5y-7x+xy-xy=19-35}} \right. \\⇔\left \{\matrix {{4x+9y=3} \hfill\cr {7x+5y=16}} \right. \\⇔\left \{\matrix {{28x+63y=21} \hfill\cr {28x+20y=64}} \right. \\⇔\left \{\matrix {{43y=-43} \hfill\cr {4x+6y=3}} \right. \\⇔\left \{\matrix {{y=-1} \hfill\cr {x=3}} \right. \\⇔\left \{\matrix {{x=3} \hfill\cr {y=-1}}\right.$
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