Theorem: MyRing.add_right_cancelαα (MIL/C02_Basics/S02_Proving_Identities_in_Algebraic_Structures.lean)

State before:
R : Type u_1
inst✝ : Ring R
a b c : R
h : a + b = c + b
⊢ a = c
Tactic:
rw [← add_neg_cancel_right a b, h, add_neg_cancel_right]
State after:
no goals