$x^2–5xy–x+5y+1=0$

1 bình luận về “$x^2–5xy–x+5y+1=0$”

1. x^2-5xy-x+5y+1=0

   =>x(x-5y)-(x-5y)=-1

   =>(x-1)(x-5y)=-1

   => $[\begin{array}{l}\{\begin{array}{l}x-1=1\\ x-5y=-1\end{array}\\ \{\begin{array}{l}x-1=-1\\ x-5y=1\end{array}\end{array}$ => $[\begin{array}{l}\{\begin{array}{l}x=2\\ y={\displaystyle \frac{3}{5}}\end{array}\\ \{\begin{array}{l}x=0\\ x=-{\displaystyle \frac{1}{5}}\end{array}\end{array}$ 

     =>(x;y)={(2;3/5);(0;-1/5)}

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