Question

Giari hệ phương trình: \(\left\{{}\begin{matrix}1.5x+1.25y=150 \\1.2x+1.2y=132\end{matrix}\right.\)

Answer 1

\(\left\{{}\begin{matrix}1,5x+1,25y=150\\1,2x+1,2y=132\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}1,8x+1,5y=180\\1,8x+1,8y=198\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}1,8x+1,5y=180\\-0,3y=-18\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}1,8x+1,5y=180\\y=60\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}1,8x+1,5\times60=180\\y=60\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}1,8x=90\\y=60\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=50\\y=60\end{matrix}\right.\)

Vậy hệ phương trình có nghiệm là \(\left(50;60\right)\)