x - cena jednego pączka
y - cena jednego soku
[tex] \begin{cases} 2x + y = 4 \\ 3x + 2y = 7\end{cases}[/tex]
[tex] \begin{cases} y = 4 - 2x \\ 3x + 2y = 7\end{cases}[/tex]
[tex] \begin{cases} y = 4 - 2x \\ 3x + 2(4 - 2x) = 7\end{cases}[/tex]
[tex] \begin{cases} y = 4 - 2x \\ 3x + 8 - 4x = 7\end{cases}[/tex]
[tex] \begin{cases}y = 4 - 2x \\ - x = - 1\end{cases}[/tex]
[tex] \begin{cases}y = 4 - 2x \\ x = 1 \end{cases}[/tex]
[tex] \begin{cases}y = 4 - 2 \times 1 \\ x = 1 \end{cases}[/tex]
[tex] \begin{cases}y = 4 - 2 \\ x = 1 \end{cases}[/tex]
[tex] \begin{cases}y = 2 \\ x = 1 \end{cases}[/tex]
Odp. Pączek kosztuje 1 złoty, a sok 2 złote.
