\[(x + 35) - 48 = 68\]
\[Подставим\ x = 26;45;81:\]
\[(26 + 35) - 48 = 61 - 48 =\]
\[= 13 \neq 68\]
\[(45 + 35) - 48 = 80 - 48 =\]
\[= 32 \neq 68\]
\[(81 + 35) - 48 = 116 - 48 =\]
\[= 68 - подходит.\]
\[Ответ:x = 81.\]