Metamath Proof Explorer


Theorem resubidaddid1

Description: Any real number subtracted from itself forms a left additive identity. (Contributed by Steven Nguyen, 8-Jan-2023)

Ref Expression
Assertion resubidaddid1 ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ) → ( ( 𝐴 𝐴 ) + 𝐵 ) = 𝐵 )

Proof

Step Hyp Ref Expression
1 readdsub ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ 𝐴 ∈ ℝ ) → ( ( 𝐴 + 𝐵 ) − 𝐴 ) = ( ( 𝐴 𝐴 ) + 𝐵 ) )
2 1 3anidm13 ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ) → ( ( 𝐴 + 𝐵 ) − 𝐴 ) = ( ( 𝐴 𝐴 ) + 𝐵 ) )
3 repncan2 ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ) → ( ( 𝐴 + 𝐵 ) − 𝐴 ) = 𝐵 )
4 2 3 eqtr3d ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ) → ( ( 𝐴 𝐴 ) + 𝐵 ) = 𝐵 )