3 * (x - 8y - 17) = 3 * 0
3x - 24y - 51 = 0
(3x - 24y - 51) = 0
-(3x + 4y - 23) = 0
--------------------- -28y - 28 = 0
-28y = 28
y = 28 / -28
y = -1
x - 8(-1) - 17 = 0
x + 8 - 17 = 0
x - 9 = 0
x = 9
Ответ: x = 9, y = -1