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Theorem muleqadd 8200
Description: Property of numbers whose product equals their sum. Equation 5 of [Kreyszig] p. 12. (Contributed by NM, 13-Nov-2006.)
Assertion
Ref Expression
muleqadd  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( ( A  x.  B )  =  ( A  +  B )  <-> 
( ( A  - 
1 )  x.  ( B  -  1 ) )  =  1 ) )

Proof of Theorem muleqadd
StepHypRef Expression
1 ax-1cn 7501 . . . . 5  |-  1  e.  CC
2 mulsub 7942 . . . . . 6  |-  ( ( ( A  e.  CC  /\  1  e.  CC )  /\  ( B  e.  CC  /\  1  e.  CC ) )  -> 
( ( A  - 
1 )  x.  ( B  -  1 ) )  =  ( ( ( A  x.  B
)  +  ( 1  x.  1 ) )  -  ( ( A  x.  1 )  +  ( B  x.  1 ) ) ) )
31, 2mpanr2 430 . . . . 5  |-  ( ( ( A  e.  CC  /\  1  e.  CC )  /\  B  e.  CC )  ->  ( ( A  -  1 )  x.  ( B  -  1 ) )  =  ( ( ( A  x.  B )  +  ( 1  x.  1 ) )  -  ( ( A  x.  1 )  +  ( B  x.  1 ) ) ) )
41, 3mpanl2 427 . . . 4  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( ( A  - 
1 )  x.  ( B  -  1 ) )  =  ( ( ( A  x.  B
)  +  ( 1  x.  1 ) )  -  ( ( A  x.  1 )  +  ( B  x.  1 ) ) ) )
51mulid1i 7553 . . . . . . 7  |-  ( 1  x.  1 )  =  1
65oveq2i 5679 . . . . . 6  |-  ( ( A  x.  B )  +  ( 1  x.  1 ) )  =  ( ( A  x.  B )  +  1 )
76a1i 9 . . . . 5  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( ( A  x.  B )  +  ( 1  x.  1 ) )  =  ( ( A  x.  B )  +  1 ) )
8 mulid1 7548 . . . . . 6  |-  ( A  e.  CC  ->  ( A  x.  1 )  =  A )
9 mulid1 7548 . . . . . 6  |-  ( B  e.  CC  ->  ( B  x.  1 )  =  B )
108, 9oveqan12d 5687 . . . . 5  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( ( A  x.  1 )  +  ( B  x.  1 ) )  =  ( A  +  B ) )
117, 10oveq12d 5686 . . . 4  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( ( ( A  x.  B )  +  ( 1  x.  1 ) )  -  (
( A  x.  1 )  +  ( B  x.  1 ) ) )  =  ( ( ( A  x.  B
)  +  1 )  -  ( A  +  B ) ) )
12 mulcl 7532 . . . . 5  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( A  x.  B
)  e.  CC )
13 addcl 7530 . . . . 5  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( A  +  B
)  e.  CC )
14 addsub 7756 . . . . . 6  |-  ( ( ( A  x.  B
)  e.  CC  /\  1  e.  CC  /\  ( A  +  B )  e.  CC )  ->  (
( ( A  x.  B )  +  1 )  -  ( A  +  B ) )  =  ( ( ( A  x.  B )  -  ( A  +  B ) )  +  1 ) )
151, 14mp3an2 1262 . . . . 5  |-  ( ( ( A  x.  B
)  e.  CC  /\  ( A  +  B
)  e.  CC )  ->  ( ( ( A  x.  B )  +  1 )  -  ( A  +  B
) )  =  ( ( ( A  x.  B )  -  ( A  +  B )
)  +  1 ) )
1612, 13, 15syl2anc 404 . . . 4  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( ( ( A  x.  B )  +  1 )  -  ( A  +  B )
)  =  ( ( ( A  x.  B
)  -  ( A  +  B ) )  +  1 ) )
174, 11, 163eqtrd 2125 . . 3  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( ( A  - 
1 )  x.  ( B  -  1 ) )  =  ( ( ( A  x.  B
)  -  ( A  +  B ) )  +  1 ) )
1817eqeq1d 2097 . 2  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( ( ( A  -  1 )  x.  ( B  -  1 ) )  =  1  <-> 
( ( ( A  x.  B )  -  ( A  +  B
) )  +  1 )  =  1 ) )
191addid2i 7688 . . . 4  |-  ( 0  +  1 )  =  1
2019eqeq2i 2099 . . 3  |-  ( ( ( ( A  x.  B )  -  ( A  +  B )
)  +  1 )  =  ( 0  +  1 )  <->  ( (
( A  x.  B
)  -  ( A  +  B ) )  +  1 )  =  1 )
2112, 13subcld 7856 . . . 4  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( ( A  x.  B )  -  ( A  +  B )
)  e.  CC )
22 0cn 7543 . . . . 5  |-  0  e.  CC
23 addcan2 7726 . . . . 5  |-  ( ( ( ( A  x.  B )  -  ( A  +  B )
)  e.  CC  /\  0  e.  CC  /\  1  e.  CC )  ->  (
( ( ( A  x.  B )  -  ( A  +  B
) )  +  1 )  =  ( 0  +  1 )  <->  ( ( A  x.  B )  -  ( A  +  B ) )  =  0 ) )
2422, 1, 23mp3an23 1266 . . . 4  |-  ( ( ( A  x.  B
)  -  ( A  +  B ) )  e.  CC  ->  (
( ( ( A  x.  B )  -  ( A  +  B
) )  +  1 )  =  ( 0  +  1 )  <->  ( ( A  x.  B )  -  ( A  +  B ) )  =  0 ) )
2521, 24syl 14 . . 3  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( ( ( ( A  x.  B )  -  ( A  +  B ) )  +  1 )  =  ( 0  +  1 )  <-> 
( ( A  x.  B )  -  ( A  +  B )
)  =  0 ) )
2620, 25syl5rbbr 194 . 2  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( ( ( A  x.  B )  -  ( A  +  B
) )  =  0  <-> 
( ( ( A  x.  B )  -  ( A  +  B
) )  +  1 )  =  1 ) )
2712, 13subeq0ad 7866 . 2  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( ( ( A  x.  B )  -  ( A  +  B
) )  =  0  <-> 
( A  x.  B
)  =  ( A  +  B ) ) )
2818, 26, 273bitr2rd 216 1  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( ( A  x.  B )  =  ( A  +  B )  <-> 
( ( A  - 
1 )  x.  ( B  -  1 ) )  =  1 ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 103    <-> wb 104    = wceq 1290    e. wcel 1439  (class class class)co 5668   CCcc 7411   0cc0 7413   1c1 7414    + caddc 7416    x. cmul 7418    - cmin 7716
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-in1 580  ax-in2 581  ax-io 666  ax-5 1382  ax-7 1383  ax-gen 1384  ax-ie1 1428  ax-ie2 1429  ax-8 1441  ax-10 1442  ax-11 1443  ax-i12 1444  ax-bndl 1445  ax-4 1446  ax-14 1451  ax-17 1465  ax-i9 1469  ax-ial 1473  ax-i5r 1474  ax-ext 2071  ax-sep 3965  ax-pow 4017  ax-pr 4047  ax-setind 4368  ax-resscn 7500  ax-1cn 7501  ax-icn 7503  ax-addcl 7504  ax-addrcl 7505  ax-mulcl 7506  ax-addcom 7508  ax-mulcom 7509  ax-addass 7510  ax-mulass 7511  ax-distr 7512  ax-i2m1 7513  ax-1rid 7515  ax-0id 7516  ax-rnegex 7517  ax-cnre 7519
This theorem depends on definitions:  df-bi 116  df-3an 927  df-tru 1293  df-fal 1296  df-nf 1396  df-sb 1694  df-eu 1952  df-mo 1953  df-clab 2076  df-cleq 2082  df-clel 2085  df-nfc 2218  df-ne 2257  df-ral 2365  df-rex 2366  df-reu 2367  df-rab 2369  df-v 2624  df-sbc 2844  df-dif 3004  df-un 3006  df-in 3008  df-ss 3015  df-pw 3437  df-sn 3458  df-pr 3459  df-op 3461  df-uni 3662  df-br 3854  df-opab 3908  df-id 4131  df-xp 4460  df-rel 4461  df-cnv 4462  df-co 4463  df-dm 4464  df-iota 4995  df-fun 5032  df-fv 5038  df-riota 5624  df-ov 5671  df-oprab 5672  df-mpt2 5673  df-sub 7718  df-neg 7719
This theorem is referenced by:  conjmulap  8259
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