решите систему линейных уравнений (x+y)/9 - (x-y)/3=2 (2x - y)/6 - (3x+2y)/3=-20

( Х + y ) /9 - ( X - y ) / 3 = 2 X + y - 3( X - y ) = 18 X + y - 3x + 3y = 18 - 2x + 4y = 18 2y - X = 9 - x = 9 - 2y –------------/2x - y - 2( 3x + 2y ) = - 120 2x - y - 6x - 4y = - 120 - 4x - 5y = - 120 - X - 1,25y = - 30 9 - 2y - 1,25y = - 30 - 3,25y = - 39 y = 12- X = 9 - 24 = - 15 X = 15 Ответ ( 15 ; 12 )