Question

x + 3y = 10
3x + y = 14

Answer 1

Resposta:

x + 3y = 10

3x + y = 14

$x = 10 - 3y \\ \\ 3 \times (10 - 3y) + y = 14 \\ 30 - 9y + y = 14 \\ 30 - 8y - 14 = 0 \\ 16 - 8y = 0 \\ - 8y = - 16 \times ( - 1) \\ 8y = 16 \div (8) \\ y = 2 \\ \\ x = 10 - 3y \\ x = 10 - 3 \times 2 \\ x = 10 - 6 \\ x = 4 \\ \\ (x.y) = (4.2)$