Respuesta :

[tex]\begin{gathered} \begin{bmatrix}x+3=y \\ 3x+4y=7\end{bmatrix} \\ \end{gathered}[/tex][tex]\begin{gathered} x+3=y \\ x+3-3=y-3 \\ x=y-3 \end{gathered}[/tex]

then

[tex]\begin{gathered} 3\mleft(y-3\mright)+4y=7 \\ 3y-9+4y=7 \\ 7y-9=7 \\ 7y-9+9=7+9 \\ 7y=16 \\ \frac{7y}{7}=\frac{16}{7} \\ y=\frac{16}{7} \end{gathered}[/tex]

replacing in x

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