а) х × 28 = 336
х = 336 : 28
х = 12
12 × 28 = 336
336 = 336
б) 312 : х = 8
х = 312 : 8
х = 39
312 : 39 = 8
8 = 8
в) 16 × х - 11 * х = 225
5 * х = 225
х = 225 : 5
х = 45
16 × 45 - 11 × 45 = 225
225 = 225
