Question

{ 2x + y = 7 x - y = -1

Answer 1

$x = - \frac{2}{9} \\ \\ y = - \frac{5}{9}$

Explicação passo-a-passo:

$2x + y = 7x - y = - 1 \\ \\ 2x + y = - 1 \\ 7x - y = - 1 \\ \\ y = - 1 - 2x \\ \\ 7x - ( - 1 - 2x) = - 1 \\ 7x + 1 + 2x = - 1 \\ 7x + 2x = - 1 - 1 \\ 9x = - 2 \\ x = - \frac{ 2}{9} \\ \\ 2( - \frac{2}{9} ) + y = - 1 \\ \\ - \frac{4}{9} + y = - 1 \\ \\ y = - 1 + \frac{4}{9} \\ \\ y = - \frac{5}{9}$