A=17²⁰⁰⁸-(11+3)²⁰⁰⁸

A=17²⁰⁰⁸-14²⁰⁰⁸

A=13²⁰⁰⁸

chu so hang don vi cua A la 8

sorry incorect

A=17-11-3

=3

bằng 17 mũ 2008-11 mũ 2008 =6 mũ 2008-3 mũ 2008 =3 mũ 2008

A= 17^2008 - 11^2008 - 3^2008

A=(17^4)^502 - 11^2008 - (3^4)^502

A=83521^502 - 11^2008 - 81^502

A=(...1) - (...1) - (...1)

A=(...9).

Vậy chữ số hàng đơn vị của A là (...9).

A=\(17^{2008}-11^{2008}-3^{2008}\)

A=\(\left(17^4\right)^{502}-11^{2008}-\left(3^4\right)^{502}\)

A=\(83521^{502}-11^{2008}-81^{502}\)
A=\(\left(......1\right)-\left(.......1\right)-\left(........1\right)\)

A=\(\left(.........9\right)\)

Vậy A có chữ số tận cùng là 9

2)M=\(17^{25}+24^4-13^{21}\)

M=\(17^{24}\cdot17+\left(24^2\right)^2-13^{20}\cdot13\)

M=\(\left(17^4\right)^6\cdot17+576^2-\left(13^4\right)^5\cdot13\)

M=\(83521^6\cdot17+\left(......6\right)-28561^5\cdot13\)

M=\(\left(.......1\right)\cdot17+\left(........6\right)-\left(.........1\right)\cdot13\)

M=\(\left(........7\right)+\left(..........6\right)-\left(...........3\right)\)

M=\(\left(...........0\right)⋮10\)

Vậy M\(⋮10\)

a) 17²⁰⁰⁸  = (17⁴)⁵⁰² = (...1)⁵⁰² = (....1)

11²⁰⁰⁸ = (....1)

3²⁰⁰⁸ = (3⁴)⁵⁰² = (...1)⁵⁰²  = (...1)

=> 17²⁰⁰⁸ - 11²⁰⁰⁸ - 3²⁰⁰⁸ = (...1) - (...1) - (...1)

Hiệu 17²⁰⁰⁸ - 11²⁰⁰⁸ tận cùng là 0 => 17²⁰⁰⁸ - 11²⁰⁰⁸ - 3²⁰⁰⁸ tận cùng là 9

b) 17²⁵ = (17⁴)⁶.17 = (...1)⁶.17 = (...7)

24⁴ = (24²)² = (...6)² = (...6)

13²¹ = (13⁴)⁵.13 = (...1)⁵.13 = (...3)

=> B = 17²⁵ - 24⁴ - 13²¹ = (...7) + (...6) - (....3) = (....0) => B chia hết cho 10

c) Tương tự

B=(17⁴)⁵⁰² -11²⁰⁰⁸ - (3⁴)⁵⁰² = (....1)⁵⁰² -....1  - (...1)⁵⁰² =....1 -.....1 - ....1 = ....0-   .....1 =.....9