Question

giải hệ pt

x-4y=3

2x-y=4

Answer 1

\(\left\{{}\begin{matrix}x-4y=3\\2x-y=4\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}2x-8y=6\\2x-y=4\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}2x-8y-2x+y=6-4\\2x-y=4\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}-7y=2\\2x=y+4\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}y=-\dfrac{2}{7}\\2x=-\dfrac{2}{7}+4=\dfrac{26}{7}\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}y=-\dfrac{2}{7}\\x=\dfrac{13}{7}\end{matrix}\right.\)