3 65 7 2 19 7
18x---- + -----x----- - -----x18 + ----- / 1 ----
7 100 13 7 13 13
3 2 13 7 19 13
=18x（--- - ---）+ --- x --- + ----x-----
7 7 20 13 13 20
18 13 271 61
=------ + --- = ------------- = 3 -----
7 10 70 70