5•( X + 2y ) - 3 = X + 5 ;
5x + 10y - 3 = X + 5 ;
4x + 10y = 8 ;
y + 4•( X - 3y ) = 50 ;
y + 4x - 12y = 50 ;
4x - 11y = 50
- 4x + 11y = - 50 ;
4x - 4x + 10y + 11y = 8 - 50 ;
21y = - 42 ;
y = - 2 ;
4x + 10y = 8 ;
4x - 20 = 8 ;
4x = 28
X = 7. Ответ ( 7 ; - 2 )