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2 agende si 4 pixuri costa 16 lei iar 4 agende si 20 de pixuri costa 68 lei cat costa o agenda si cat costa un pix

Răspuns :

[tex]\left\{\begin{matrix}
2a + 4p = 16 \: | \times ( - 2) \\ 4a + 20p = 68\end{matrix}\right.[/tex]

[tex]\left\{\begin{matrix}
- 4a - 8p = - 32\\

4a + 20p = 68\end{matrix}\right.[/tex]

[tex] - 4a + 4a - 8p + 20p = - 32 + 68[/tex]

[tex]12p = 36[/tex]

[tex]p = \frac{36}{12} [/tex]

[tex]p = 3[/tex]

[tex]2a + 4p = 16[/tex]

[tex]2a + 4 \times 3 = 16[/tex]

[tex]2a + 12 = 16[/tex]

[tex]2a = 16 - 12[/tex]

[tex]2a = 4[/tex]

[tex]a = \frac{4}{2} [/tex]

[tex]a = 2[/tex]