\[\boxed{\mathbf{Страница\ 34.\ }\mathbf{Еуроки\ - \ ДЗ\ без\ мороки}}\]
\[\boxed{\mathbf{13.\ }}\]
\[\textbf{а)}\ 16 - a = a + 4\]
\[2a = 16 - 4\]
\[2a = 12\]
\[при\ a = 6.\]
\[\textbf{б)}\ 23 - a = a + 17\]
\[2a = 23 - 17\]
\[2a = 6\]
\[при\ a = 3.\]
\[\textbf{в)}\ 18 + a = 10 - a\]
\[нет\ таких\ a.\]
\[\textbf{г)}\ a + 11 = 19 - a\]
\[2a = 19 - 11\]
\[2a = 8\]
\[при\ a = 4.\]
\[\boxed{\mathbf{14.\ }}\]
\[\textbf{а)}\ 17 - c > c + 12\]
\[при\ c = 1;2.\]
\[\textbf{б)}\ 4 + c < 11 - c\]
\[при\ c = 1;2;3.\]
\[\textbf{в)}\ 24 - c > 12 + c\]
\[при\ c = 1;2;3;4;5.\]
\[\textbf{г)}\ c + 8 < 16 - c\]
\[при\ c = 1;2;3.\]
\[\boxed{\mathbf{15.\ }}\]
\[\textbf{а)}\ a - 8 > 12 - a\ на\ 2:\]
\[при\ a = 11.\]
\[\textbf{б)}\ 6 - a < a - 4\ \ на\ 2:\]
\[при\ a = 4.\]
\[\textbf{в)}\ 13 - a > a + 9\ \ на\ 2:\]
\[при = 1.\]
\[\textbf{г)}\ a + 12 < 19 - a\ \ на\ 3:\]
\[при\ a = 5.\]
\[\mathbf{9.\ Буквенная\ запись\ свойств\ сложение\ и\ вычитания}\]