1/3x+1/4x+1/5x=1,19/75

1/3 * x + 1/4 * x + 1/5 * x = 1 19/75;

1/3 * x + 1/4 * x + 1/5 * x = 75/75 + 19/75;

Умножим уравнение на 60.

1/3 * x * 60 + 60 * 1/4 * x + 60 * 1/5 * x = 75/75 * 60 + 60 * 19/75;

60/3 * x + 60/4 * x + 60/5 * x = 1 * 60 + 4 * 19/5;

20 * x + 15 * x + 12 * x = 60 + 76/5;

20 * x + 27 * x = 60 + 15.2;

47 * x = 75.2;

x = 75.2/47;

x = 1.6;

Ответ: х = 1,6.