Question

Cho A=3+3^2+3^3+3^4+3^5+3^6+3^7+3^8+3^9

Chung minh A chia het cho 3,Giup minh nhe,ai nhanh mk tick cho nha

Answer 1

Vì A=3+3^1+3^2+....+3^9 => A=3*(1+3^1+3^2+....+3^8) Mà 3 chia hết cho 3=>A chia hết cho 3

Answer 2

A= 3( 1+3+3^2+3^3+3^4+3^5+3^6+3^7+3^8) chia hết cho 3

Answer 3

mk ko hieu ban co the giai thich ra duoc ko