5/2-5/3х=х-11/2
5/2+11/2=х+5/3х
16/2=8/3х
8/3х=16/2
х=16/2 / 8/3
х=16/2*3/8
х=3
А) 278 : 1/6 = 278 * 6 = 1668
82 : 1/7 = 82 * 7 = 574
115 : 1/9 = 115 * 9 = 1035
б) 78 * 1/3 = 78 : 3 = 26
252 * 1/6 = 252 : 6 = 42
128 * 1/8 = 128 : 8 = 16
Схема в приложении.
--------------------------------
B - 7m +2n
-3p+5x -2y
-a + 4b - 8x + 3y
-13a+2
-10y +6a
2a -1
19y +48k
-2x-18
1,6x + 4,4y
2/5 - 2/3 a