xy-2x+y=-2 giúp mik nha nhanh giúp mik ạ

xy-2x+y=-2 giúp mik nha nhanh giúp mik ạ

2 bình luận về “xy-2x+y=-2 giúp mik nha nhanh giúp mik ạ”

  1. xy – 2x + y = -2
    => xy – 2x + y + 2=  0
    => x(y – 2) + (y – 2)+  4=  0
    => x(y – 2) + (y – 2) = – 4
    => (y – 2)(x + 1) = -4
    => -4 \vdots x + 1
    => x +1 \in Ư(-4)
    => x +1 \in {+-1,+-2,+-4}
    Ta có bảng sau:
    \begin{array}{|c|c|c|}\hline \text{x + 1}&\text{1}&\text{-1}&\text{2}&\text{-2}&\text{4}&\text{-4}\\\hline \text{y – 2}&\text{-4}&\text{4}&\text{-2}&\text{2}&\text{-1}&\text{1}\\\hline \text{x}&\text{0}&\text{-2}&\text{1}&\text{-3}&\text{3}&\text-5{}\\\hline \text{y}&\text{-2}&\text{6}&\text{0}&\text{4}&\text{1}&\text{3}\\\hline \text{KL}&\text{tm}&\text{tm}&\text{tm}&\text{tm}&\text{tm}&\text{tm}\\\hline\end{array}
    Vậy (x,y) \in{(0,-2);(-2,6);(1,0);(-3,4);(3,1);(-5,3)}

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