{ 4x - 5y =10,
x = (19 - 2y) / 3;
4* ((19 - 2y) / 3) - 5y = 10;
(76 - 8y) / 3 - 5y -10 = 0;
приведем все к общему знаменателю:
(76 - 8y) / 3 -15y / 3 - 30/3 = 0;
76 - 8y - 15y -30 =0;
-22y +46 = 0; -22y = -46; 22y = 46; y = 46 / 22 = 2.09
x = (19 - 2*2.09)/3 = (19 - 4.18) / 3 = 14/82 / 3 = 4.94
Ответ: x = 4.94; y = 2.09