Question

x + y = 2
3x +2y= 10


x - y =10
2x + y = 20

Answer 1

Resposta:

x + y = 2

3x +2y= 10

$x = 2 - y \\ \\ 3 \times (2 - y) + 2y = 10 \\ 6 - 3y + 2y = 10 \\ 6 - y = 10 \\ 6 - y - 10 = 0 \\ - y - 4 = 0 \\ - y = 4 \times ( - 1) \\ y = - 4 \\ \\ x = 2 - y \\ x = 2 - ( - 4) \\ x = 2 + 4 \\ x = 6 \\ \\ (x.y) = (6. - 4)$

x - y =10

2x + y = 20

$x = 10 + y \\ \\ 2 \times (10 + y) + y = 20 \\ 20 + 2y + y = 20 \\ 20 + 3y - 20 = 0 \\ 3y = 0 \div (3) \\ y = 0 \\ \\ x = 10 + y \\ x = 10 + 0 \\ x = 10 \\ \\ (x.y) = (10.0)$