Theorem problem1

Description: Practice problem 1. Clues: 5p4e9 3p2e5 eqtri oveq1i . (Contributed by Filip Cernatescu, 16-Mar-2019) (Proof modification is discouraged.)

	Ref	Expression
Assertion	problem1	⊢ ( ( 3 + 2 ) + 4 ) = 9

Proof

Step	Hyp	Ref	Expression
1		3p2e5	⊢ ( 3 + 2 ) = 5
2	1	oveq1i	⊢ ( ( 3 + 2 ) + 4 ) = ( 5 + 4 )
3		5p4e9	⊢ ( 5 + 4 ) = 9
4	2 3	eqtri	⊢ ( ( 3 + 2 ) + 4 ) = 9