Question

Tìm x biết xy - x + 2y=3

Answer 1

\(\Leftrightarrow xy+2y=3+2\)

\(\Rightarrow xy+2y=5\)

\(\Rightarrow y\left(2+x\right)=5\)

\(\Rightarrow y=5:\left(2+x\right)\) (1*)

<=>2+x\(\in\){1;-1;5;-5}

=>x\(\in\){-1,-3,3,-7}

dựa vào (1*) =>x=y=-1;-3;3;-7