Description: Commutative/associative law. (Contributed by Scott Fenton, 3-Jan-2013)
Ref | Expression | ||
---|---|---|---|
Assertion | mul31 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | mulcom | |
|
2 | 1 | oveq2d | |
3 | 2 | 3adant1 | |
4 | mulass | |
|
5 | mulcl | |
|
6 | 5 | ancoms | |
7 | 6 | 3adant1 | |
8 | simp1 | |
|
9 | 7 8 | mulcomd | |
10 | 3 4 9 | 3eqtr4d | |