6x + 3 = 5x - 20y - 16
6x - 5x + 20y = -16 - 3
x + 20y = -19
6x - 9y - 6x = 8 - y
-9y + y = 8
-8y = 8
y = -1
x + 20(-1) = -19
x - 20 = -19
x = -19 + 20
x = 1
Ответ: (1; -1)