Question

b)
(2x + y = 15
x - 3y = 25​

Answer 1

Resposta:

2x + y = 15

y = 15 - 2x

x - 3 . 15 - 2x = 25

x - 45 - 2x = 25

x - 2x = 25 + 45

- x = 70 (-1)

x = - 70

y = 15 - 2 . (-70)

y = 15 + 140

y = 155

Par ordenados: {x = - 70 e y = 155}