Question

{2x-4y=-15
{6x+2y=-20

Answer 1

Explicação passo-a-passo:

$2x - 4y = - 15 \\ 6x + 2y = - 20$

$2x - 4y = - 15 \\ 6x + 2y = - 20 \: \: \: \times 2$

$2x - 4y = - 15 \\ 12x + 4y = - 40$

$2x + 12x - 4y + 4y = - 15 + ( - 40)$

$14x = - 55$

$x = \frac{ - 55}{14}$

$2x - 4y = - 15$

$2 \times ( - \frac{55}{14} ) - 4y = - 15$

$- \frac{55}{7} - 4y = - 15$

$- \frac{55}{7} = - 15 + 4y$

$4y = - \frac{55}{7} + 15$

$4y = \frac{50}{7}$

$y = \frac{\frac{50}{7}}{4}$

$y = \frac{25}{14}$

$x = - \frac{55}{14}$

$x = \frac{25}{14}$