Theorem: MyGroup.left_inv_eq_right_inv (IIScExperiments/Solutions/GroupTheorySolutions.lean)

State before:
G : Type
inst✝ : MyGroup G
a✝ b✝ c✝ a b c : G
h1 : b * a = 1
h2 : a * c = 1
⊢ b = c
Tactic:
have h : b * (a * c) = (b * a) * c := (mul_assoc b a c).symm
State after:
G : Type
inst✝ : MyGroup G
a✝ b✝ c✝ a b c : G
h1 : b * a = 1
h2 : a * c = 1
h : b * (a * c) = b * a * c
⊢ b = c

State before:
G : Type
inst✝ : MyGroup G
a✝ b✝ c✝ a b c : G
h1 : b * a = 1
h2 : a * c = 1
h : b * (a * c) = b * a * c
⊢ b = c
Tactic:
simpa [h2, h1] using h
State after:
no goals