Помогите решить срочно! (0,75-5/6):78-23*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]