Question

B.
( x + 3y = 7
(5x + 2y = 9​

Answer 1

Resposta:

$x + 3y = 7 \\ 3y = 7 - x \\ y =14 + \frac{7 - x}{3 } \\ \\ 5x + 2y = 9 \\ 5x + 2 \times \frac{7 - x}{3} = \\ 5x + \frac{2(7 - x)}{3} = 5x + \frac{14 - 2x}{3} = \frac{14 + 3x}{3} = \\ 14 + 3x = 3 \\ 3x = 3 - 14 \\ 3x = - 11 \\ x = - \frac{11}{3} =$

$- \frac{11}{3} + 3y = 7 \\ 3y = \frac{11}{3} \\ y = \frac{11}{3} \times 3 = \\ y = \frac{33}{3} = \\ y = 11$

$y = - \frac{ 11}{3} \\ x = 11$