Question

GIẢI HỆ PHƯƠNG TRÌNH

\(x+y=460\)

0,85x + 0,9 y= 403

Answer 1

\(\left\{{}\begin{matrix}x+y=460\\0,85x+0,9y=403\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=460-y\\0,85\left(460-y\right)+0,9y=403\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=460-y\\391-0,85y+0,9y=403\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=460-y\\0,05y=12\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=460-240\\y=240\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=220\\y=240\end{matrix}\right.\)