Question

Giúp mik vs ạ

      cần gấpp

Answer 1

Câu 3:

1: x^2-5x+4=0

=>\(\left(x-1\right)\left(x-4\right)=0\)

=>\(\left[{}\begin{matrix}x=1\\x=4\end{matrix}\right.\)

2: \(\left\{{}\begin{matrix}x-2y=1\\2x+y=7\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x-2y=1\\4x+2y=14\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}5x=15\\2x+y=7\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=3\\y=7-2x=1\end{matrix}\right.\)