2.64/112=2.8/4х-3.1 3. (3/8х): 14=3: 4 2/3 решите плс

2 8/4х=4х; 2)64/112=4х-31/10; 4/7+31/10=4х; 40/70+217/70=4х; 257/70*1/4=х; х=257/280 3)3/8х:14=3:4 2/3; 3/8х:14=3/1*3/14; 3/8х=9/14*14/1; х=9/1*8/3; х=24; ответ: х=24