Question

помогите написать математику​

Answer 1

Пошаговое объяснение:

4) Приведем к общему знаменателю все и сократим.

$19-8\frac{7}{8} -4\frac{5}{6} +2 \frac{8}{9} = \\19 -\frac{71}{8} -\frac{29}{6} +\frac{26}{9}= \\19 -\frac{71}{2*4} -\frac{29}{2*3} +\frac{26}{3*3} = \\19 -\frac{71}{8} -\frac{29}{6} +\frac{26}{9}= \\19 -\frac{71*3}{2*4*3} -\frac{29*4}{2*3*4} +\frac{26}{3*3} = \\19 -\frac{213}{2*4*3} -\frac{116}{2*3*4} +\frac{26}{3*3} = \\19 -\frac{97*3}{2*3*4*3} +\frac{26*2*4}{3*3*2*4} = \\19 +\frac{-291+208}{3*3*2*4} = \frac{1368-83}{72} = \frac{1285}{72} = 17 \frac{61}{72}$

5)

$(19\frac{5}{21} - 8\frac{9}{14} ) -6\frac{5}{7} =\\(19\frac{5}{7*3} - 8\frac{9}{7*2} ) -6\frac{5}{7} =\\(19\frac{5*2}{7*3*2} - 8\frac{9*3}{7*2*3} ) -6\frac{5}{7} =\\(19\frac{10}{42} - 8\frac{27}{42} ) -6\frac{5}{7} =\\(18\frac{52}{42} - 8\frac{27}{42} ) -6\frac{5}{7} =\\10\frac{25}{42} -6\frac{5*6}{7*6} =\\9\frac{67}{42} -6\frac{30}{42} =3\frac{37}{42}$