Question

sistema de ecuacion con metodo de sustitucion
$- 3 \times +y = 12 \\ - y + 9 \times = 0 \\ \\ \\ 3 \times - y = 1 \\ 5 \times - 3 = 12y$
por fisss es para hoy y si no me ponen cero ​

Answer 1

Explicación paso a paso:

$1 \\ 2x - 5y = 12 \\ 3x + 4y = - 5 \\ \\ 2x = 12 + 5y \\ x = \frac{12 + 5y}{2} \\ 3 \times \frac{12 + 5y}{2} + 4y = - 5 \\ \frac{36 + 15y}{2} + \frac{8y}{2} = - 5 \\ \frac{36 + 15y + 8y}{2} = - 5 \\ 36 + 23y = - 10 \\ 23y = - 10 - 36 \\ 23y = - 46 \\ 23y = - 46 \\ y = \frac{ - 46}{23} = - 2 \\ y = - 2 \\ x = \frac{12 + 5y}{2} = \frac{12 + 5( - 2)}{2} = \frac{12 - 10}{2} = \frac{2}{2} = 1 \\ x = 1 \\ 2 \times 1 - 5( - 2) = 2 - ( - 10) = 12 \\ 3 \times 1 + 4( - 2) = 3 + ( - 8) = - 5$

$2) \\ 5x - 7y = - 1 \\ - 3x + 4y = - 24 \\ 5x = - 1 + 7y \\ x = \frac{ - 1 + 7y}{5} \\ - 3 \times \frac{ - 1 + 7y}{5} + 4y = - 24 \\ \frac{3 - 21y}{5} + \frac{20y}{5} = - 24 \\ \frac{3 - 21y + 20y}{5} = - 24 \\ \frac{3 - y}{5} = - 24 \\ 3 - y = - 120 \\ - y = - 120 - 3 \\ - y = - 123 \\ y = 123$

$x = \frac{ - 1 + 7y}{5} = \frac{ - 1 + 7(123)}{5} = \frac{ - 1 + 861}{5} = \frac{860}{5} = 172 \\ x = 172$

$3) \\ - 3x + y = 12 \\ - y + 9x = 0 \\ - y = - 9x \\ y = 9x \\ - 3x + 9x = 12 \\ 6x = 12 \\ x = \frac{12}{6} = 2 \\ x = 2 \\ y = 9x = 9 \times 2 = 18 \\ y = 18$

$4) \\ 3x - 8y = 1 \\ 5x - 3 = 12y \\ 5x = 12y + 3 \\ x = \frac{12y + 3}{5} \\ 3 \times \frac{12y + 3}{5} - 8y = 1 \\ \frac{36y + 9}{5} - \frac{40y}{5} = 1 \\ \frac{36y + 9 - 40y}{5} = 1 \\ \frac{ - 4y + 9}{5} = 1 \\ - 4y + 9 = 5 \\ - 4y = 5 - 9 \\ - 4y = - 4 \\ 4y = 4 \\ y = \frac{4}{4} = 1$

$x = \frac{12y + 3}{5} = \frac{12 \times 1 + 3}{5} = \frac{12 + 3}{5} = \frac{15}{5} = 3$

$x = 3$

espero te sirva