1) 25 - 4x = 12 - 5x; -4х + 5х = 12 - 25; х = -13
2) 13x + 27 = 16x + 4,5; 13x - 16x = 4,5 - 27; -3х = -22,5; х = 7,5;
3) 5 - 3x = 2x - 8; - 3x - 2x = -5 - 8; -5x = -13; x = 2,6;
4)
5) x - 2/3 = 5/6x; x + 5/6x = 2/3; 11/6x = 2/3; x = 4/11;
6) 1целая 4/5y = y + 4; 9/5y - y = 4; 4/5y = 4; y = 5;