Question

porfa vor en los tres metodos reducción, igualacion y sustitución porfa es para mañana ​

Answer 1

Respuesta:

1/

$x - 2y = - 7 \\ - 2x + 2y = 2 \\ - x = - 5 \\ x = 5 \\ \\ x - 2y = - 7 \\ - 2y = - 7 - x \\ 2y = 7 + x \\ y = \frac{7 + x}{2} = \frac{7 + 5}{2} = \frac{12}{2} = 6$

$x - 2y = 5 - 2 \times 6 = 5 - 12 = - 7 \\ - 2x + 2y = - 2 \times 5 + 2 \times 6 = - 10 + 12 = 2$

2/

$x - 2y = - 7 \\ x = - 7 + 2y \\ - 2x + 2y = 2 \\ - 2x = 2 - 2y \\ 2x = - 2 + 2y \\ x = \frac{ - 2 + 2y}{2} \\ \frac{ - 2 + 2y}{2} = - 7 + 2y \\ - 2 + 2y = - 14 + 4y \\ 14 - 2 = 4y - 2y \\ 12 = 2y \\ y = \frac{12}{2} = 6 \\ x = \frac{ - 2 + 2y}{2} = \frac{ - 2 + 2 \times 6}{2} = \\ = \frac{ - 2 + 12}{2} = \frac{10}{2} = 5$

$3) \\ x - 2y = - 7 \\ x = - 7 + 2y \\ \\ - 2x + 2y = 2 \\ - 2( - 7 + 2y) + 2y = 2 \\ 14 - 4y + 2y = 2\\ 14 - 2y = 2 \\ - 2y = 2- 14 \\ - 2y = - 12 \\ 2y = 12 \\ y = \frac{12}{2} = 6 \\ x = - 7 + 2y = - 7 + 2 \times 6 \\ = - 7 + 12 = 5 \\ x = 5$