Ответ:
a-b=2 => a = 2+b
4a+2b-5c = 8 => 8 + 4b - 5c = 8 = 4b - 5c = 0
a+ 2c = 19 => 2 + b + 2c = 19 => b + 2c = 17.
4b - 5c = 0
b + 2c = 17 /*4 => 4b + 8c = 68
.
4b - 5c = 0
4b + 8c = 68
-
-5c - 8c = -68
-13c = -68
c = 68/13
.
4b + 8c = 68 => 4b + 8*68/13 =68 => 4b * 13 = 68 * (13 - 8) => b = 68 * 5/(13*4)
a = 2 + b => a = 2 + 68 * 5/(13*4) = a = 13*4*2 + 68 * 5.
Пошаговое объяснение: