A =\(\frac{\frac{12}{13}+\frac{12}{131}-\frac{12}{1313}+\frac{12}{13131}}{\frac{15}{13}+\frac{15}{131}-\frac{15}{1313}+\frac{15}{13131}}=\frac{12.\left(\frac{1}{13}+\frac{1}{131}-\frac{1}{1313}+\frac{1}{13131}\right)}{15.\left(\frac{1}{13}+\frac{1}{131}-\frac{1}{1313}+\frac{1}{13131}\right)}=\frac{12}{15}=\frac{4}{5}\) 

Tick ủng hộ nha mọi người

\(\dfrac{\left(12:13\right)+\left(12:131\right)-\left(12:1313\right)+\left(12:13131\right)}{\left(15:13\right)+\left(15:131\right)-\left(15:1313\right)+\left(15:13131\right)}\\ =\dfrac{12:\left(13+131-1313+13131\right)}{15:\left(13+131-1313+13131\right)}=\dfrac{12}{15}=\dfrac{4}{5}\)

Bạn đợi chút nghe, tối nay mình làm cho

=>B=\(\frac{12.\left(\frac{1}{13}+\frac{1}{1313}+\frac{1}{131}+\frac{1}{1313}\right)}{15.\left(\frac{1}{13}+\frac{1}{1313}+\frac{1}{131}+\frac{1}{1313}\right)}\)

=>B=\(\frac{12}{15}\)

=>B=\(\frac{4}{5}\)

B = \(\frac{12.\left(\frac{1}{13}+\frac{1}{1313}+\frac{1}{131}-\frac{1}{1313}\right)}{15.\left(\frac{1}{13}+\frac{1}{131}-\frac{1}{1313}+\frac{1}{1313}\right)}\)

=\(\frac{12.\left(\frac{1}{13}+\frac{1}{131}\right)}{15.\left(\frac{1}{13}+\frac{1}{131}\right)}\)

=\(\frac{12}{15}=\frac{4}{5}\)

Vậy B = 4/5.

B=\(\frac{\frac{12}{13}+\frac{12}{1313}+\frac{12}{131}-\frac{13}{1313}}{\frac{15}{13}+\frac{15}{131}-\frac{15}{1313}+\frac{15}{1313}}\)

B=\(\frac{\frac{12}{13}+\frac{12}{131}}{\frac{15}{13}+\frac{15}{131}}\)

B=\(\frac{12\cdot\left(\frac{1}{13}+\frac{1}{131}\right)}{15\cdot\left(\frac{1}{13}+\frac{1}{131}\right)}\)

Chia cả tử và mẫu B cho \(\frac{1}{13}\)+\(\frac{1}{131}\)(rút gọn phân số)

Ta được:B=\(\frac{12}{15}\)=\(\frac{4}{5}\)

Ta có 1212/1313= 12/13

=> 1212/1313 =12/13

=> 1212/1313 =12/13 

nha bạn

5/7>6/21

18/24>15/25

12/13=1212/1313

\(\dfrac{5}{7}\)>\(\dfrac{6}{21}\)

\(\dfrac{18}{24}\)>\(\dfrac{15}{25}\)

\(\dfrac{12}{13}\)=\(\dfrac{1212}{1313}\)

a) \(\dfrac{12}{14}=\dfrac{1200}{1400}=\dfrac{1400-200}{1400}=1-\dfrac{200}{1400}\)

\(\dfrac{1212}{1414}=\dfrac{1414-200}{1414}=1-\dfrac{200}{1414}\)

vì \(\dfrac{200}{1414}< \dfrac{200}{1400}\)

Nên \(1-\dfrac{200}{1400}< 1-\dfrac{200}{1414}\)

Vậy \(\dfrac{12}{14}< \dfrac{1212}{1414}\)

Các bài sau tương tự

a/\(\frac{1212}{1313}=\frac{12x101}{13x101}=\frac{12}{13}\)

Vậy \(\frac{12}{13}=\frac{1212}{1313}\)

b/Ta có:

\(\frac{4}{5}< 1\)

\(\frac{10}{9}>1\)

=>\(\frac{4}{5}< 1< \frac{10}{9}\Rightarrow\frac{4}{5}< \frac{10}{9}\)

c/\(\frac{17}{15}=1+\frac{2}{15}\)

\(\frac{31}{29}=1+\frac{2}{29}\)

Vì \(\frac{2}{15}>\frac{2}{29}\) nên \(\frac{17}{15}>\frac{31}{29}\)

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chú ý: dấu "=>" có nghĩa là "suy ra"

D(=)

E(<)

F(>)

d là =

e là 4/5<10/9

f là 17/15>31/29