Question

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

Answer 1

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

$\left\{\begin{matrix} - 4a - 8p = - 32\\ 4a + 20p = 68\end{matrix}\right.$

$- 4a + 4a - 8p + 20p = - 32 + 68$

$12p = 36$

$p = \frac{36}{12}$

$p = 3$

$2a + 4p = 16$

$2a + 4 \times 3 = 16$

$2a + 12 = 16$

$2a = 16 - 12$

$2a = 4$

$a = \frac{4}{2}$

$a = 2$