Description: Product of two sums. (Contributed by Mario Carneiro, 27-May-2016)
Ref | Expression | ||
---|---|---|---|
Hypotheses | mulm1d.1 | |
|
mulnegd.2 | |
||
subdid.3 | |
||
muladdd.4 | |
||
Assertion | muladdd | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | mulm1d.1 | |
|
2 | mulnegd.2 | |
|
3 | subdid.3 | |
|
4 | muladdd.4 | |
|
5 | muladd | |
|
6 | 1 2 3 4 5 | syl22anc | |