解：(1/6+2/3-2/7-3/14)÷1/42=(1/6+2/3-2/7-3/14)×42=7+28-12-9=14∴原式=-1/14
-1/42÷(1/6+2/3-2/7-3/14)=-1÷(42×1/6+42×2/3-42×2/7-42×3/14)=-1÷（7+28-12-9）=-1÷14=-1/14
