Đáp án:
Giải thích các bước giải:
$xy+3x-y=-2$
$⇔x.(y+3)-y-3=-2-3$
$⇔x.(y+3)-(y+3)=-5$
$⇔(x-1).(y+3)=-5=-5.1=1.(-5)=-1.5=5.(-1)$
$TH1:(x-1).(y+3)=-5.1$
$⇒x=-4;y=-2$
$TH2:(x-1).(y+3)=1.(-5)$
$⇒x=2;y=-8$
$TH3:(x-1).(y+3)=-1.5$
$⇒x=0;y=2$
$TH4:(x-1).(y+3)=5.(-1)$
$⇒x=6;y=-4$
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