Description: The square of 9 is 81. (Contributed by SN, 30-Mar-2025)
Ref | Expression | ||
---|---|---|---|
Assertion | sq9 | |- ( 9 ^ 2 ) = ; 8 1 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 9cn | |- 9 e. CC |
|
2 | 1 | sqvali | |- ( 9 ^ 2 ) = ( 9 x. 9 ) |
3 | 9t9e81 | |- ( 9 x. 9 ) = ; 8 1 |
|
4 | 2 3 | eqtri | |- ( 9 ^ 2 ) = ; 8 1 |