rewrite [Nat.mul_div_cancel _ (Nat.add_pos_right _ zero_lt_one)]
n m k d x : ℕ
h₂ : x + 1 ∣ m
hd : m = (x + 1) * d
⊢ n / (x + 1) * (x + 1) / (x + 1) / d = n / ((x + 1) * d)
n m k d x : ℕ
h₂ : x + 1 ∣ m
hd : m = (x + 1) * d
⊢ n / (x + 1) / d = n / ((x + 1) * d)