Ответ :
Ответ:
[tex]x=\frac{4}{5}=0,8[/tex].
[tex]x=1\frac{4}{7}[/tex].
Пошаговое объяснение:
[tex]8\frac{7}{10}-x=7\frac{9}{10}\\\\x=8\frac{7}{10}-7\frac{9}{10}\\\\x=7\frac{17}{10}-7\frac{9}{10}\\\\x=\frac{8}{10}\\\\x=\frac{4}{5}=0,8[/tex]
[tex](\frac{2}{7}+x)-\frac{5}{7}=1\frac{1}{7}\\\\\frac{2}{7}+x-\frac{5}{7}=1\frac{1}{7}\\\\x=1\frac{1}{7}-\frac{2}{7}+\frac{5}{7}\\\\x=\frac{8}{7}-\frac{2}{7}+\frac{5}{7}\\\\x=\frac{6}{7}+\frac{5}{7}\\\\x=\frac{11}{7}\\\\x=1\frac{4}{7}[/tex]