theorem extracted_formal_statement_14.{u_1} {Ω : Type u_1} {m : MeasurableSpace Ω} {μ : Measure Ω}
  [inst : IsFiniteMeasure μ] {X : Ω → ℝ} {t a b : ℝ} (hX : AEMeasurable X μ) (h : ∀ᵐ (ω : Ω) ∂μ, X ω ∈ Set.Icc a b)
  (ht : t < 0) (ω : Ω) : rexp (t * X ω) = rexp (-t * -X ω) := sorry

State before:
case h
Ω : Type u_1
m : MeasurableSpace Ω
μ : Measure Ω
inst✝ : IsFiniteMeasure μ
X : Ω → ℝ
t a b : ℝ
hX : AEMeasurable X μ
h : ∀ᵐ (ω : Ω) ∂μ, X ω ∈ Set.Icc a b
ht : t < 0
ω : Ω
⊢ rexp (t * X ω) = rexp (-t * -X ω)

Tactic: rw [(by ring : -t * (-X ω) = t * X ω)]

State after:

Relevant lemmas: