Metamath Proof Explorer


Theorem congsub

Description: If two pairs of numbers are componentwise congruent, so are their differences. (Contributed by Stefan O'Rear, 2-Oct-2014)

Ref Expression
Assertion congsub A B C D E A B C A D E A B - D - C E

Proof

Step Hyp Ref Expression
1 simp11 A B C D E A B C A D E A
2 simp12 A B C D E A B C A D E B
3 simp13 A B C D E A B C A D E C
4 simp2l A B C D E A B C A D E D
5 4 znegcld A B C D E A B C A D E D
6 simp2r A B C D E A B C A D E E
7 6 znegcld A B C D E A B C A D E E
8 simp3l A B C D E A B C A D E A B C
9 simp3r A B C D E A B C A D E A D E
10 congneg A D E A D E A - D - E
11 1 4 6 9 10 syl22anc A B C D E A B C A D E A - D - E
12 congadd A B C D E A B C A - D - E A B + D - C + E
13 1 2 3 5 7 8 11 12 syl322anc A B C D E A B C A D E A B + D - C + E
14 2 zcnd A B C D E A B C A D E B
15 4 zcnd A B C D E A B C A D E D
16 14 15 negsubd A B C D E A B C A D E B + D = B D
17 3 zcnd A B C D E A B C A D E C
18 6 zcnd A B C D E A B C A D E E
19 17 18 negsubd A B C D E A B C A D E C + E = C E
20 16 19 oveq12d A B C D E A B C A D E B + D - C + E = B - D - C E
21 13 20 breqtrd A B C D E A B C A D E A B - D - C E