Question

11^9+11^8+11^7+.....+11^1+11^0

Answer 1

Đặt A=11⁹+11⁸+11⁷+...+11¹+11⁰

Ta có: 11A=11¹⁰+11⁹+11⁸+...+11²+11¹

-

             A=11⁹+11⁸+11⁷+...+11¹+11⁰

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=>11A-A=10A=11¹⁰-11⁰=11¹⁰-1

=>A=(11¹⁰-1):10

Chúc bạn học giỏi nha

K cho mik vs nhé quang văn tèo

Answer 2

Đặt A = 11^9 + 11^8 + 11^7 + ... + 11^1 + 11^0

11A = 11^10 + 11^9 + 11^8 + ... + 11^2 + 11^1

11A - A = (11^10 + 11^9 + 11^8 + ... + 11^2 + 11^1) - (11^9 + 11^8 + 11^7 + ... + 11^1 + 11^0)

10A = 11^10 - 11^0

10A = 11^10 - 1

A = 11^10 - 1/10

Answer 3

Thank kiu