Реши система уравнений 1.28. 1) 2x - 3y = -18, xy = -12; (x + y = 65, 2) 2x - 3y = -19, xy = -6; 3) xy = 28. 1.29. 1) y-x= 1, x + y = 1; 3) x? - 3y = -5, 7x + 3y = -1. 1x + y = 4, 1.30. 1) x + y - 3/xy = 1; (x - 1 + y = 4, 2) (x+y = 3; 1 1 2) y-1 y +1 y? -x-9 = 0; X 3) x + y = 5, x + y = 35;
если до двух
1)54x36
2)357x
3)395y
3)4883x-467y