a: \(-\dfrac{11}{33}< 0< \dfrac{25}{16}\)

b: \(-\dfrac{17}{23}=\dfrac{-171717}{232323}\)

a) \(\frac{-8}{-70}=\frac{8}{70}\left(=\frac{4}{35}\right)\)
   \(\frac{-1}{-28}=\frac{1}{28}\)
   \(\frac{27}{-180}=\frac{-27}{180}\left(=\frac{-3}{20}\right)\)

b) \(\frac{18}{-45}=\frac{-18}{45}\left(=\frac{-2}{5}\right)\)
   \(\frac{-151515}{252525}=\frac{-151515}{252525}\left(=\frac{-3}{5}\right)\)
   \(\frac{7777}{-1111}=\frac{-7777}{1111}\left(=\frac{-7}{1}=-7\right)\)

Ta có: \(\frac{2000}{-2001}=-\frac{2000}{2001}=-\left(\frac{2001-1}{2001}\right)=-\left(\frac{2001}{2001}-\frac{1}{2001}\right)=-\left(1-\frac{1}{2001}\right)=-1+\frac{1}{2001}\)

       \(-\frac{2003}{2002}=-\left(\frac{2002+1}{2002}\right)=-\left(\frac{2002}{2002}+\frac{1}{2002}\right)=-\left(1+\frac{1}{2002}\right)=-1-\frac{1}{2002}\)

Vì \(\frac{1}{2001}>-\frac{1}{2002}\) nên \(-1+\frac{1}{2001}>-1-\frac{1}{2002}\)

hay \(\frac{2000}{-2001}>-\frac{2003}{2002}\)

Do đó 

em mới lớp 5

Cách 1 :

Ta có : \(1-\frac{4}{11}=\frac{7}{11};1-\frac{8}{15}=\frac{7}{15}\)

Vì \(\frac{7}{11}>\frac{7}{15}\)nên \(\frac{4}{11}< \frac{8}{15}\).

Cách 2 :

Vì \(\frac{4}{11}< \frac{4}{8}=\frac{1}{2};\frac{1}{2}=\frac{8}{16}< \frac{8}{15}\)nên \(\frac{4}{11}< \frac{8}{15}\).

~ HOK TỐT ~

Cách 1:

  \(1-\frac{4}{11}=\frac{7}{11}\)

\(1-\frac{8}{15}=\frac{7}{15}\)

Vì \(\frac{7}{11}>\frac{7}{15}\Rightarrow\frac{4}{11}< \frac{8}{15}\)

Cách 2:

     \(\frac{4}{11}=\frac{60}{165}\)

      \(\frac{8}{15}=\frac{88}{165}\)

Vì \(\frac{60}{165}< \frac{88}{165}\)

\(\Rightarrow\frac{4}{11}< \frac{8}{15}\)

Cách 3:

    Ta có:

 \(\frac{4}{11}=\frac{8}{22}< \frac{8}{15}\)

\(\Rightarrow\frac{4}{11}< \frac{8}{15}\)

      Cách 4:

\(\frac{4}{11}-1=\frac{-7}{11}\)

\(\frac{8}{15}-1=\frac{-7}{15}\)

Vì \(\frac{-7}{11}< \frac{-7}{15}\)\(\Rightarrow\frac{4}{11}< \frac{8}{15}\)

\(\frac{327}{326}=1\frac{1}{326}\) còn \(\frac{326}{325}=1\frac{1}{325}\)

bây giờ ta chỉ còn so sánh \(1\frac{1}{326}\)với \(1\frac{1}{325}\)

1 = 1 so sánh \(\frac{1}{326}\)với \(\frac{1}{325}\)

so sánh phân số có cùng tử số thì phân số nào có mấu số bé hơn thì phân số đó lớn hơn

vậy \(\frac{1}{326}< \frac{1}{325}\)=> \(\frac{327}{326}< \frac{326}{325}\)

                                                                 Đáp số : \(\frac{327}{326}< \frac{326}{325}\)

a) Vì \(-45< -16\) nên \(\left(-\dfrac{45}{17}\right)^{15}< \left(\dfrac{-16}{17}\right)^{15}\)

b) Vì \(21< 23\) nên \(\left(-\dfrac{8}{9}\right)^{21}< \left(-\dfrac{8}{9}\right)^{23}\)

c) \(27^{40}=3^{3^{40}}=3^{120}\)

\(64^{60}=8^{2^{60}}=8^{120}\)

Vì \(3< 8\) nên \(3^{120}< 8^{120}\) hay \(27^{40}< 64^{60}\)

\(-\frac{13}{15}+-\frac{2}{15}=-1;-\frac{14}{16}+-\frac{2}{16}\)

Vì \(-\frac{2}{15}< -\frac{2}{16}\Rightarrow\frac{-13}{15}< -\frac{14}{16}\)

2.Gọi 3 p/số đó là x;y;z

\(-\frac{5}{8}< x< y< z< -\frac{3}{5}\)

\(-\frac{100}{160}< x< y< z< -\frac{96}{160}\)

\(\Rightarrow x=-\frac{99}{160};y=-\frac{98}{160}=-\frac{49}{80};z=-\frac{97}{160}\)