Решите систему уравнений

6x+3=5x-4(5y+4)
3(2x-3y)-6x=8-y

6x+3=5x-4(5y+4)
3(2x-3y)-6x=8-y

6x+3=5x-20y-16
6x-9y-6x=8-y

6x+3-5x+20y+16=0
6x-9y-6x-8+y=0

x+20y=-19
-8y=8

y= -1
x= -19-20y

y=-1
x=-19+20=1

Ответ: (1; -1).