Question

GIẢI HỆ PHƯƠNG TRÌNH: \(\left\{{}\begin{matrix}\dfrac{2x-y}{3}=x+y+1\\X-3y-5=\dfrac{2x-y}{2}\end{matrix}\right.\)

Answer 1

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

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

=>\(\left\{{}\begin{matrix}2x-y-3x-3y=3\\2x-6y-10-2x+y=0\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}-x-4y=3\\-5y=10\end{matrix}\right.\)

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

=>\(\left\{{}\begin{matrix}y=-2\\x=-3-4y=-3-4\cdot\left(-2\right)=8-3=5\end{matrix}\right.\)