Помогите решить срочно! (0,75-5/6):7\8-2\3*0.5

[latex](0,75- \frac{5}{6} ):\frac{7}{8}-\frac{2}{3}*0.5 = (\frac{3}{4}- \frac{5}{6} )*\frac{8}{7}-\frac{2}{3}*\frac{1}{2} = \\ =(\frac{9}{12}- \frac{10}{12} )*\frac{8}{7}-\frac{1}{3} = -\frac{1}{12}*\frac{8}{7}-\frac{1}{3} = \\ = -\frac{8}{12*7}-\frac{1}{3} =-\frac{2}{3*7}-\frac{7}{3*7} =-\frac{9}{21}= -\frac{3}{7} \\ [/latex]