a) A = 13! - 11! = 1.2.3...13 - 1.2.3...1 = 2.(1.3...13 - 1.3...11) chia hết cho 2

b) Tương tự a) ta cũng có b chia hết cho 5

c) A = 13! - 11! = 11! . (12.13 - 1) = 11! . 155 chia hết cho 155

a co ,b

co, c ko

Ai giải giúp mik với, mik cần gấp lắm !!!!!!!!! Thanks những người nào giải giúp nha, nhớ giải chi tiết mik mới **** đó !!!!!!!!

a ) Ta có :

A = 13 ! - 11 ! = 1 . 2 . 3 . ...... . 13 - 1 . 2 . 3 ... 11

              = 2 . ( 1 . 3 . 4 .... 13 - 1 . 3 . 4 ....11 ) chia hết cho 2

Vây A chia hết cho 2

b ) Làm tương tự 

c ) A = 13 ! - 11 ! = 11! . 12 . 13 - 11!

                         = 11! . ( 12 . 13 - 1 )

                         = 11! . 155 chia hết cho 155

Vậy A chia hết cho 155

A=13!-11!

A=1.2.3....12.13-1.2.3....10.11

A=618 710 400

a)A chia hết cho 2 ( vì có số cuối là 0)

b)A chia hết cho 5( vì có số cuối là 0)

C)A chia hết cho 155( vì a>155 và 155=5.31)

\(A=13!-11!=1.2.3.4.5.6.7.8.9.10.11.12.13-1.2.3.4.5.6.7.8.9.10.11\)

a) \(13!⋮2\)\(11!⋮2\)\(\Rightarrow A⋮2\)

b) \(13!⋮5\)\(11!⋮5\)\(\Rightarrow A⋮5\)

c) \(A=13!-11!=1.2.3.4.5.6.7.8.9.10.11.12.13-1.2.3.4.5.6.7.8.9.10.11\)

\(=1.2.3.4.5.6.7.8.9.10.11.\left(12.13-1\right)\)

\(=1.2.3.4.5.6.7.8.9.10.11.155\)

\(\text{​​}\Rightarrow A⋮155\)

a) có

b) có

c) có

a) có

b) có

c) có 

k mình nha

*13! chia hết cho 2

11! chia het cho 2=>13!-11! chia hết cho 2

*13! chia het cho 5

11! chia het cho 5=>3!-11! chia het cho 5

*155=5.31

13! ko chia hết cho 5.31

11! ko chia het cho 5.31=>13!-11! ko chia het cho 155

a)A chia hết cho 2

b)A chia hết cho 5

c)A ko chia het cho 155

**** GIÙM MÌNH NHA

a) 13! = 13.12.11....5.4.3.2.1 => 13! chia hết cho 2 và 5

11! = 11.10.9....5.4.3.2.1 => 11! chia hết cho 2 và 5

=> A = 13! - 11! chia hết cho 2 và 5

c) A = 13! - 11! = 13.12.11! - 11! = (13.12 - 1) .11! = 155.11! chia hết cho 155

Vậy A chia hết cho 155

cảm ơn Trần Thị

 Loan nhé

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 \(A=13!-11!\)

\(A=11!\cdot12\cdot13-11!\)

\(A=11!\left(12\cdot13-1\right)\)

\(A=11!\cdot155\)

\(\Rightarrow\)A chia hết cho 2 ( vì trong 11! chứa thừa số 2 )

         A chia hết cho 5

         A chia hết cho 155

a)A có chia hết cho 2

b)A có chia hết cho 5

c)A có chia hết cho 155