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2
2
20x 15x 17 20x 30x 100 15 83 15 83 83 x x x 15Vậy 83S x x15 x xx xx x 5 2 2 3 5x x x x x x f) 5 2 22
1 3
53 2 3 4
2
2
4 5 2 6 2 4 3 3.5 20x 8 12x2
6x 4x 12x2
15x12 1226 8 11 37 8 37 8 8 . Vậy 8x x x x x 37S x x37x x x x x x 10.2 5 2