2 5 7 x 4 1 2
- 2 5 7 х 4 1 2
- 6 2 5 x 2 7 x 4 1 3
- 2 x 1 5 )- 7 4 x 0 25 )+ 2
- 5 2 5 x 2 1 7 x 4 2 3
- 5 2x 1 )- 3 3x 2 )= 7 x 4
- 4 1 6 х 3 2 7 2 5 7 x 4 1 6
- 2 3 4 x 2 )= 5 2x 1 2 7 4x
- 2 4 7 x 2 5 1 6 7
- 1 2 7 9 x 4 2 5 x
- 13x 5 x 2 )= 4 2x 1 )+ 7
- 2 5 x 3 7 2 5 x 4 7 1 10
- 2 3x 5 x 4 7 1 2
- X 1 5 2 7 4 và 1 2
- 2 2x 4 )- 7 5 x 1
- 7 3x 2 )- 5 4x 3 4 x 2 )+ 1