Metamath Proof Explorer


Theorem div12

Description: A commutative/associative law for division. (Contributed by NM, 30-Apr-2005)

Ref Expression
Assertion div12 ABCC0ABC=BAC

Proof

Step Hyp Ref Expression
1 divcl BCC0BC
2 1 3expb BCC0BC
3 mulcom ABCABC=BCA
4 2 3 sylan2 ABCC0ABC=BCA
5 4 3impb ABCC0ABC=BCA
6 div13 BCC0ABCA=ACB
7 6 3comr ABCC0BCA=ACB
8 divcl ACC0AC
9 8 3expb ACC0AC
10 mulcom ACBACB=BAC
11 9 10 stoic3 ACC0BACB=BAC
12 11 3com23 ABCC0ACB=BAC
13 5 7 12 3eqtrd ABCC0ABC=BAC