Ta có: \(\dfrac{20}{39}>\dfrac{20}{41}>\dfrac{18}{41}\left(1\right)\)

\(\dfrac{22}{27}>\dfrac{22}{29}\left(2\right)\)

Lại có: \(\dfrac{18}{43}=1-\dfrac{25}{43}\)

\(\dfrac{14}{49}=1-\dfrac{25}{39}\)

Vì \(\dfrac{25}{43}< \dfrac{25}{39}\)

⇒ \(1-\dfrac{25}{43}< 1-\dfrac{25}{39}\left(3\right)\)

Từ (1) (2) (3) ⇒ A<B

cai kia sai mk giải lại nha

Ta có \(\dfrac{20}{39}>\dfrac{20}{41}>\dfrac{18}{41}\left(1\right)\)

\(\dfrac{22}{27}>\dfrac{22}{29}\left(2\right)\)

Lại có: \(\dfrac{18}{43}=1-\dfrac{25}{43}\)

\(\dfrac{14}{39}=1-\dfrac{25}{39}\)

Vì: \(\dfrac{25}{43}< \dfrac{25}{39}\)

⇒ \(1-\dfrac{25}{39}>1-\dfrac{25}{43}\left(3\right)\)

Từ (1) (2) (3) ⇒ A>B

biểu thức 2 lớn hơn ạ!

làm như nào b ơi

A= 8044

B=4050151

A<B

a<b

\(7.2^{100}< 8.2^{100}=2^3.2^{100}=2^{103}\)

cảm ơn nhìu ạ

9( x + 28 ) = 39 + 51 

9( x + 28 ) = 90

    x + 28   =  90 : 9 

    x  + 28 = 10 

           x   = -18 

9(x+28)=39+51

9(x+28)=90

(x+28)=90/9

(x+28)=10

x=10-28

x=-18

\(A=17\left(\frac{2}{7.13}+\frac{3}{13.22}+\frac{5}{22.37}+\frac{4}{37.49}\right)\)

\(=\frac{17}{3}\left(\frac{6}{7.13}+\frac{9}{13.22}+\frac{15}{22.37}+\frac{12}{37.49}\right)\)

\(=\frac{17}{3}\left(\frac{1}{7}-\frac{1}{13}+\frac{1}{13}-\frac{1}{22}+\frac{1}{22}-\frac{1}{37}+\frac{1}{37}-\frac{1}{49}\right)\)

\(=\frac{17}{3}\left(\frac{1}{7}-\frac{1}{49}\right)\)

\(B=13\left(\frac{3}{7.16}+\frac{5}{16.31}+\frac{4}{31.43}+\frac{2}{43.49}\right)\)

\(=\frac{13}{3}\left(\frac{9}{7.16}+\frac{15}{16.31}+\frac{12}{31.43}+\frac{6}{43.49}\right)\)

\(=\frac{13}{3}\left(\frac{1}{7}-\frac{1}{16}+\frac{1}{16}-\frac{1}{31}+\frac{1}{31}-\frac{1}{43}+\frac{1}{43}-\frac{1}{49}\right)\)

\(=\frac{13}{3}\left(\frac{1}{7}-\frac{1}{49}\right)\)

\(\Rightarrow\frac{A}{B}=\frac{\frac{17}{3}\left(\frac{1}{7}-\frac{1}{49}\right)}{\frac{13}{3}\left(\frac{1}{7}-\frac{1}{49}\right)}=\frac{\frac{17}{3}}{\frac{13}{3}}=\frac{17}{13}\)

A=34/7.13+51/13.22+85/22.37+68/37.49

  =17(2/7.13+3/13.22+5/22.37+4/37.49)

  =17/3(6/7.13+9/13.22+15/22.37+12/37.49)

  =17/3(1/7-1/13+1/13-1/22+1/22-1/37+1/37-1/49)

  =17/3(1/7-1/49) b=13(3/7.16+5/16.31+4/31.43+2/43.49)

B=13/3(9/7.16+15/16.31+12/31.43+6/43.49)

  =13/3(9/7.16+15/16.31+12/31.43+6/43.49)

 =13/3(1/7-1/16+1/16-1/31+1/31-1/43+1/43-1/49)

 =13/3(1/7-1/49)