Toán Lớp 8: Tìm x, thuộc Z biết x^2 – x – 6 = – y^2
Leave a reply
Register Now
Login
Lost Password
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Toán Lớp 8: Tìm x, thuộc Z biết x^2 – x – 6 = – y^2
Comments ( 1 )
{x^2} + x + 6 = {y^2}\\
\Leftrightarrow {(2x + 1)^2} – {(2y)^2} = – 23\\
\Leftrightarrow (2x + 1 – 2y)(2x + 1 + 2y) = – 23\\
\Rightarrow \left[ \begin{array}{l}
2x + 1 – 2y = – 23\\
2x + 1 + 2y = 1
\end{array} \right. \Rightarrow \left[ \begin{array}{l}
x = – 6\\
y = 6
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
2x + 1 – 2y = – 1\\
2x + 1 + 2y = 23
\end{array} \right. \Rightarrow \left[ \begin{array}{l}
x = 5\\
y = 6
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
2x + 1 – 2y = 1\\
2x + 1 + 2y = – 23
\end{array} \right. \Rightarrow \left[ \begin{array}{l}
x = – 6\\
y = – 6
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
2x + 1 – 2y = 23\\
2x + 1 + 2y = – 1
\end{array} \right. \Rightarrow \left[ \begin{array}{l}
x = 5\\
y = – 6
\end{array} \right.
\end{array}\]