[tex]2.8:\frac{4}{7} -2.8*\frac{4}{7} =\frac{28}{10} *\frac{7}{4} -\frac{28}{10} *\frac{4}{7} =\frac{49}{10} -\frac{16}{10} =\frac{33}{10} =3.3\\\\3.3 :0.6=5.5[/tex]