Question

5x + 2y =70
x + y =20

Answer 1

Resposta:

x = 20 - y

5. (20 - y) + 2y = 70

100 - 5y + 2y = 70

- 3y = 70 - 100 .(-1)

3y = - 70 + 100

3y = 30

y = 30/3

y = 10

x = 20 - 10

x = 10

{x = 10, y = 10}