Question

Giair hệ phương trình hepllllllllll

Answer 1

\(\left\{{}\begin{matrix}x_1^2-x_2^2=6\\x_1+x_2=-2\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}\left(x_1-x_2\right)\left(x_1+x_2\right)=6\\x_1+x_2=-2\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x_1-x_2=-3\\x_1+x_2=-2\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}2x_1=-5\\x_1+x_2=-2\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x_1=-\dfrac{5}{2}\\-\dfrac{5}{2}+x_2=-2\end{matrix}\right.\)

\(\left\{{}\begin{matrix}x_1=-\dfrac{5}{2}\\x_2=\dfrac{1}{2}\end{matrix}\right.\)

Vậy hệ phương trình có nghiệm: \(x_1=-\dfrac{5}{2};x_2=\dfrac{1}{2}\)