| Step |
Hyp |
Ref |
Expression |
| 1 |
|
divsdird.1 |
|- ( ph -> A e. No ) |
| 2 |
|
divsdird.2 |
|- ( ph -> B e. No ) |
| 3 |
|
divsdird.3 |
|- ( ph -> C e. No ) |
| 4 |
|
divsdird.4 |
|- ( ph -> C =/= 0s ) |
| 5 |
|
1sno |
|- 1s e. No |
| 6 |
5
|
a1i |
|- ( ph -> 1s e. No ) |
| 7 |
6 3 4
|
divscld |
|- ( ph -> ( 1s /su C ) e. No ) |
| 8 |
1 2 7
|
addsdird |
|- ( ph -> ( ( A +s B ) x.s ( 1s /su C ) ) = ( ( A x.s ( 1s /su C ) ) +s ( B x.s ( 1s /su C ) ) ) ) |
| 9 |
1 2
|
addscld |
|- ( ph -> ( A +s B ) e. No ) |
| 10 |
9 3 4
|
divsrecd |
|- ( ph -> ( ( A +s B ) /su C ) = ( ( A +s B ) x.s ( 1s /su C ) ) ) |
| 11 |
1 3 4
|
divsrecd |
|- ( ph -> ( A /su C ) = ( A x.s ( 1s /su C ) ) ) |
| 12 |
2 3 4
|
divsrecd |
|- ( ph -> ( B /su C ) = ( B x.s ( 1s /su C ) ) ) |
| 13 |
11 12
|
oveq12d |
|- ( ph -> ( ( A /su C ) +s ( B /su C ) ) = ( ( A x.s ( 1s /su C ) ) +s ( B x.s ( 1s /su C ) ) ) ) |
| 14 |
8 10 13
|
3eqtr4d |
|- ( ph -> ( ( A +s B ) /su C ) = ( ( A /su C ) +s ( B /su C ) ) ) |