\(a,24=2^3.3\\ 90=2.3^2.5\\ \Rightarrow BCNN\left(24,90\right)=2^3.3^2.5=360\\ b,18=2.3^2\\ 24=2^3.3\\ \Rightarrow BCNN\left(18,24\right)=2^3.3^2=72\)

a)24=3.2^3

90=3^2.5.2

Bcnn(24,90)=3^2.5.2^3=360

b)18=3^2.2

24=3.2^3

Ưcln(18,24)=3.2=6

\(a,76=2^2\cdot19\\ 1995=3\cdot5\cdot7\cdot19\\ \RightarrowƯCLN\left(76,1995\right)=19\)

\(b,\) Gọi \(d=ƯCLN\left(2n+1,3n+1\right)\)

\(\Rightarrow2n+1⋮d;3n+1⋮d\\ \Rightarrow3\left(2n+1\right)-2\left(3n+1\right)⋮d\\ \Rightarrow1⋮d\\ \Rightarrow d=1\)

Vậy \(ƯCLN\left(2n+1,3n+1\right)=1\)

a: UCLN(76;1995)=19

24 = 2³.3

10 = 2.5

ƯCLN(24,10) = 2

BCNN(24; 10) =  2³.3.5 = 120

Ta có 16 = 24 và 24 = 23.3 ⇒ ƯCLN (16, 24) = 23 = 8.

ƯC(16 ; 24) = Ư(8) = {1 ; 2 ; 4 ; 8}.

1)

a) 18 = 2.3²

30 = 2.3.5

ƯCLN(18; 30) = 2.3 = 6

b) 24 = 2³.3

48 = 2⁴.3

ƯCLN(24; 48) = 2³.3 = 24

c) 18 = 2.3²

30 = 2.3.5

15 = 3.5

ƯCLN(18; 30; 15) = 3

d) 24 = 2³.3

48 = 2⁴.3

36 = 2².3²

ƯCLN(24; 48; 36) = 2².3 = 12

2) a) 174 = 18 . 9 + 12

18 = 12 . 1 + 6

12 = 6 . 2

Vậy ƯCLN(174; 18) = 6

b) 124 = 16 . 7 + 12

16 = 12 . 1 + 4

12 = 4 . 3

⇒ ƯCLN(124; 16) = 4

⇒ BCNN(124; 16) = 124 . 16 : 4 = 496

ƯCLN (24; 180) = 12. Mà Ư (12) = {1; 2; 3; 4; 6; 12}.

Vậy ƯC (24; 180) = {l; 2; 3; 4; 6}

UCLN=3

BCNN=120

15 = 3 . 5 
24 = 3 . 2³
60 = 5 . 3 . 2²
→ ƯCLN(15,24,60) = 3
→ BCNN(15,24,60) = 3 . 2³ . 5 = 120

Phân tích các số ra thừa số nguyên tố :

24 : 2 = 12 : 2 = 6 : 2 = 3 : 3 = 1 

Vậy 24 = 2³ x 3 

36 : 2 = 18 : 2 = 9 : 3 = 3 : 3 = 1

Vậy 36 = 2² . 3²

120 : 2 = 60 : 3 = 20 : 2 = 10 : 5 = 2 : 2 = 1 

Vậy 120 = 2³ . 3 . 5 

ƯCLN(24,36,120) = 2² . 3 = 12

BCNN ( 24,36,120) = 2³ . 3² . 5 =360

ƯCLN(24,36,120) = 4

BCNH(24,36,120) = 360

k mik nhé
 

Ta có :      24 = 2³ x 3

                36 = 2² x 3²

                120 = 2³ x 3 x 5

        ƯCLN _{( 24 ; 36 ; 120 )} = 2² x 3 = 12

           BCNN _{( 24 ; 36 ; 120 ) =} 2³ x 3^{2 x} 5 = 360

 Vậy ƯCLN = 12

       BCNN = 360