Question

Giải hệ pt 2x+y=126 y-x= 12

Answer 1

y-x=12 <=> y = x+12

2x+y=126 <=> 2x + x + 12=126

<=> 3x+12=126

<=> x = 38

<=> y = 50

Answer 2

\(\left\{{}\begin{matrix}2x+y=126\\y-x=12\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}3x=114\\y-x=12\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=38\\y=50\end{matrix}\right.\)