bé hơn bạn nhé

21/52 < 213/523

tk mk

mk tk lại cho

21/52<213/523

phân số\(\frac{213}{523}\)>\(\frac{21}{52}\)

21/52=21x523/52x523=1092/27196

                          Vì 11076/27196>1092/27196 => 21/52<213/523

213/523=213x52/523x52=11076/27196

sử dụng phép quy đồng để so sánh phân số:

 \(\frac{21}{52}=\frac{213}{523}=\frac{21.523}{52.523}=\frac{11172}{27196}=\frac{2793}{6799}\)

  \(\frac{213}{523}=\frac{21}{52}=\frac{213.52}{523.52}=\frac{11076}{13075}\)Mẫu số ghi nhầm:27196

So sánh 11172 vs 11076 thì:11172>11076

Vậy 21/52>213/523

b)

ta có : \(\frac{1313}{9191}=\frac{13}{91}=\frac{1}{7}\)

\(\frac{1111}{7373}=\frac{11}{73}>\frac{11}{77}\)

Mà \(\frac{11}{77}=\frac{1}{7}\)

\(\Rightarrow\frac{11}{73}>\frac{1}{7}\)

Vậy \(\frac{1313}{9191}< \frac{1111}{7373}\)

1-21/52=31/52     1-213/523=310/523     ta có 31/52=310/520

vì 310/520<310/523 nên 21/52 < 213/523

phần còn lại như bạn bên trên nha! chọn mk nhé!

Tự đi mà làm 

\(\frac{18}{91}< \frac{18}{90}=\frac{1}{5}\)

\(\frac{23}{114}>\frac{23}{115}=\frac{1}{5}\)

=> \(\frac{18}{91}< \frac{23}{114}\)

\(\frac{21}{52}=\frac{210}{520}=1-\frac{310}{520}\)

\(\frac{213}{523}=1-\frac{310}{523}\)

Vì \(\frac{310}{520}>\frac{310}{523}\)=> \(1-\frac{310}{520}< 1-\frac{310}{523}\)

=> \(\frac{21}{52}< \frac{213}{523}\)

\(\frac{18}{91}< \frac{18}{90}=\frac{1}{5}=\frac{23}{115}< \frac{23}{114}\)

\(=>\frac{18}{91}< \frac{23}{114}\)

 ok

213/523>21/52

21/52<213/523

ta có:21/52=210/520=1-(310/520)

         213/523=1-(310/523)

vì 1-(310/520)<1-(310/523)

suy ra:21/52<213/523

vậy 21/52<231/523

ta có:21/52=210/520=1-(310/520)

         213/523=1-(310/523)

vì 1-(310/520)<1-(310/523)

suy ra:21/52<213/523

vậy 21/52<231/523

ta có:21/52=210/520=1-(310/520)

         213/523=1-(310/523)

vì 1-(310/520)<1-(310/523)

suy ra:21/52<213/523

vậy 21/52<231/523

\(c\frac{1313}{9191}=\frac{1313:101}{9191:101}=\frac{13}{91}=\frac{1}{7}\)

\(\frac{1111}{7373}=\frac{1111:101}{7373:101}=\frac{11}{73}\)

\(mà\frac{1}{7}=\frac{1}{77}\Rightarrow\frac{11}{77}< \frac{11}{73}\)

vậy \(\frac{1313}{9191}< \frac{1111}{7373}\)

a, 18/109 < 5/30

b, 52/21 > 523/213

d, 1/3^17 < 1/5^11

Tk mk nha

18/109 < 5/30

52/21 >523/213

1/3^17 <1/5^11