Question

rezolva prin metoda substitutiei 2(x+1)-y=6 si! 3x+5y=2

Answer 1

$\left\{\begin{matrix} 2(x + 1) - y = 6\\ 3x + 5y = 2\end{matrix}\right.$

$\left\{\begin{matrix} 2x + 2 - y = 6\\ 3x + 5y = 2\end{matrix}\right.$

$\left\{\begin{matrix} 2x - y = 6 - 2\\ 3x + 5y = 2\end{matrix}\right.$

$\left\{\begin{matrix} 2x - y = 4\\ 3x + 5y = 2\end{matrix}\right.$

$2x - y = 4$

$- y = 4 - 2x \: | \times ( - 1)$

$y = 2x - 4$

$3x + 5y = 2$

$3x + 5(2x - 4) = 2$

$3x + 10x - 20 = 2$

$3x + 10x = 2 + 20$
$13x = 22$

$x = \frac{22}{13}$

$y = 2x - 4$

$y = 2 \times \frac{22}{13} - 4$

$y = \frac{44}{13} - 4$

$y = \frac{44}{13} - \frac{52}{13}$

$y = \frac{44 - 52}{13}$

$y = - \frac{8}{13}$