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Metamath Proof Explorer

Theorem bcxmaslem1

Description: Lemma for bcxmas . (Contributed by Paul Chapman, 18-May-2007)

		Ref	Expression
	Assertion	bcxmaslem1	$⊢ A = B \to (\binom{N + A}{A}) = (\binom{N + B}{B})$

Step	Hyp	Ref	Expression
1		oveq2	$⊢ A = B \to N + A = N + B$
2		id	$⊢ A = B \to A = B$
3	1 2	oveq12d	$⊢ A = B \to (\binom{N + A}{A}) = (\binom{N + B}{B})$