no goals
d₁ d₂ n₁ n₂ : Int
z₁ : d₁ ≠ 0
z₂ : d₂ ≠ 0
⊢ n₁ /. d₁ = n₂ /. d₂ ↔ n₁ * d₂ = n₂ * d₁
rcases Int.eq_nat_or_neg d₁ with ⟨_, rfl | rfl⟩ <;>
rcases Int.eq_nat_or_neg d₂ with ⟨_, rfl | rfl⟩ <;>
simp_all [divInt_neg', Int.ofNat_eq_zero, Int.neg_eq_zero,
  mkRat_eq_iff, Int.neg_mul, Int.mul_neg, Int.eq_neg_comm, eq_comm]