Question

(x+y=20
10x - 5y = 50

Answer 1

resolução!

x + y = 20 * (5)

10x - 5y = 50

________________

5x + 5y = 100

10x - 5y = 50

15x = 150

x = 150/15

x = 10

y = 20 - x

y = 20 - 10

y = 10

S = { X = 10 e Y = 10 }