∵[1/a]-[1/b]=2,
∴[b−a/ab]=2,
∴b-a=2ab,
∴a-b=-2ab,
∴原式=
2(a−b)−13ab
a−b−2ab
=
2×(−2ab)−13ab
−2ab−2ab
=[−17ab/−4ab]
=[17/4].
故答案为[17/4].
∵[1/a]-[1/b]=2,
∴[b−a/ab]=2,
∴b-a=2ab,
∴a-b=-2ab,
∴原式=
2(a−b)−13ab
a−b−2ab
=
2×(−2ab)−13ab
−2ab−2ab
=[−17ab/−4ab]
=[17/4].
故答案为[17/4].