1) 6,75х=2 1/4х-9 мсароаа
6,75x=2 1/4x-9, 6,75x-2 1/4x=-9, 6 75/100x-2 1/4x=-9, 6 3/4x-2 1/4x=-9, 4 2/4x=-9, 4,5x=-9, x=-9:4,5, x=-2. Ответ: -2
6,75x=2,25x-9 6,75x-2,25x=-9 4,5x=-9 x=-9:4,5 x=-2