Theorem deceq2 12680

Description: Equality theorem for the decimal constructor. (Contributed by Mario Carneiro, 17-Apr-2015.) (Revised by AV, 6-Sep-2021.)

Assertion

Ref	Expression
deceq2	⊢ (𝐴 = 𝐵 → ;𝐶𝐴 = ;𝐶𝐵)

Proof of Theorem deceq2

Step	Hyp	Ref	Expression
1		oveq2 7414	. 2 ⊢ (𝐴 = 𝐵 → (((9 + 1) · 𝐶) + 𝐴) = (((9 + 1) · 𝐶) + 𝐵))
2		df-dec 12675	. 2 ⊢ ;𝐶𝐴 = (((9 + 1) · 𝐶) + 𝐴)
3		df-dec 12675	. 2 ⊢ ;𝐶𝐵 = (((9 + 1) · 𝐶) + 𝐵)
4	1, 2, 3	3eqtr4g 2798	1 ⊢ (𝐴 = 𝐵 → ;𝐶𝐴 = ;𝐶𝐵)

Syntax hints:   → wi 4   = wceq 1542  (class class class)co 7406  1c1 11108   + caddc 11110   · cmul 11112  9c9 12271  ;cdc 12674

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1914  ax-6 1972  ax-7 2012  ax-8 2109  ax-9 2117  ax-ext 2704

This theorem depends on definitions:  df-bi 206  df-an 398  df-or 847  df-3an 1090  df-tru 1545  df-fal 1555  df-ex 1783  df-sb 2069  df-clab 2711  df-cleq 2725  df-clel 2811  df-rab 3434  df-v 3477  df-dif 3951  df-un 3953  df-in 3955  df-ss 3965  df-nul 4323  df-if 4529  df-sn 4629  df-pr 4631  df-op 4635  df-uni 4909  df-br 5149  df-iota 6493  df-fv 6549  df-ov 7409  df-dec 12675

This theorem is referenced by:  deceq2i  12682