Theorem 8p1e9 8526

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 8459	. 2 |- 9 = ( 8 + 1 )
2	1	eqcomi 2092	1 |- ( 8 + 1 ) = 9

Syntax hints:   = wceq 1289  (class class class)co 5634   1c1 7330   + caddc 7332   8c8 8450   9c9 8451

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 1381  ax-gen 1383  ax-ext 2070

This theorem depends on definitions:  df-bi 115  df-cleq 2081  df-9 8459

This theorem is referenced by: (None)