Решите систему уравнений 1/3(6x-y)=-3 -2(x-3y)=20

6х - y = - 3 : ( 1/3 )
6x - y = - 9
y = 6x + 9
-2( x - 3y ) = 20
x - 3y = - 10
x -3( 6x + 9 ) = - 10
x - 18x - 27 = - 10
- 17x = 17
x = - 1
y = - 6 + 9 = 3
ответ ( - 1 ; 3 )