Description: Convert a subtraction to addition using multiplication by a negative. (Contributed by NM, 2-Feb-2007)
Ref | Expression | ||
---|---|---|---|
Assertion | submul2 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | mulneg2 | |
|
2 | 1 | adantl | |
3 | 2 | oveq2d | |
4 | mulcl | |
|
5 | negsub | |
|
6 | 4 5 | sylan2 | |
7 | 3 6 | eqtr2d | |
8 | 7 | 3impb | |