Theorem 8p1e9 8239

Description: 8 + 1 = 9. (Contributed by Mario Carneiro, 18-Apr-2015.)

Assertion

Ref	Expression
8p1e9	|- ( 8 + 1 ) = 9

Proof of Theorem 8p1e9

Step	Hyp	Ref	Expression
1		df-9 8172	. 2 |- 9 = ( 8 + 1 )
2	1	eqcomi 2086	1 |- ( 8 + 1 ) = 9

Syntax hints:   = wceq 1285  (class class class)co 5543   1c1 7044   + caddc 7046   8c8 8162   9c9 8163

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-5 1377  ax-gen 1379  ax-ext 2064

This theorem depends on definitions:  df-bi 115  df-cleq 2075  df-9 8172

This theorem is referenced by: (None)