реши систему уравнений: 1/4х-у=-5 и 1/2х-1/7у=3

1/4х - y = - 5 1/2x - 1/7y = 3 Решение y = 1/4x + 5 1/2x - 1/7•( 1/4x + 5 ) = 3 1/2x - 1/28x - 5/7 = 3 14/28x - 1/28x = 3 5/7 13/28x = 26/7 13/28x = 104/28 13x = 104 X = 8