Question

Tính nhanh: 1.2.3...9-1.2.3...8-1.2.3...7.\(8^2\)

Answer 1

Trình bày lời giải đầy đủ giúp mk nha \(please\)

Answer 2

1.2.3...9 - 1.2.3...8 - 1.2.3...7.8²

= 1.2.3....8.9 - 1.2.3....8 - 1.2.3...7.8.8

= (1.2.3...8).9 - (1.2.3...8).1 - (1.2.3....7.8).8

= (1.2.3...8). (9 - 1 - 8) = (1.2.3...8) . 0 = 0