Question

помогите решить одновременые уравнени
я
х+у=20
у=3х-2​

Answer 1

Ответ:

Объяснение:

$[left{begin{gathered}x+y=20hfill\y=3x-2hfill\end{gathered}right.Leftrightarrowleft{begin{gathered}x+(3x-2)=20hfill\y=3x-2hfill\end{gathered}right.Leftrightarrowleft{begin{gathered}x+3x-2=20hfill\y=3x-2hfill\end{gathered}right.Leftrightarrow]$

$[left{begin{gathered}4x=20+2hfill\y=3x-2hfill\end{gathered}right.Leftrightarrowleft{begin{gathered}4x=22hfill\y=3x-2hfill\end{gathered}right.Leftrightarrowleft{begin{gathered}x=22div4hfill\y=3x-2hfill\end{gathered}right.Leftrightarrowleft{begin{gathered}x=5.5hfill\y=3x-2hfill\end{gathered}right.Leftrightarrow]$

$[left{begin{gathered}x=5.5hfill\y=3cdot5.5-2hfill\end{gathered}right.Leftrightarrowleft{begin{gathered}x=5.5hfill\y=14.5hfill\end{gathered}right.]$