\(a,\frac{0,75-0,6+\frac{3}{7}+\frac{3}{13}}{2,75-2,2+\frac{11}{7}+\frac{11}{13}}\)

\(=\frac{\frac{3}{4}-\frac{3}{5}+\frac{3}{7}+\frac{3}{13}}{\frac{11}{4}-\frac{11}{5}+\frac{11}{7}+\frac{11}{13}}\)

\(=\frac{3\left[\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right]}{11\left[\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right]}=\frac{3}{11}\)

Câu b tương tự

#)Giải :

b)\(\frac{5}{9}:\left(\frac{1}{3}+\frac{1}{4}\right)+\frac{5}{9}:\left(\frac{1}{9}+\frac{2}{3}\right)\)

\(=\frac{5}{9}:\frac{1}{3}+\frac{5}{9}:\frac{1}{4}+\frac{5}{9}:\frac{1}{9}+\frac{5}{9}:\frac{2}{3}\)

\(=\frac{5}{9}:\left(\frac{1}{3}+\frac{1}{4}+\frac{1}{9}+\frac{2}{3}\right)\)

\(=\frac{5}{9}:\frac{49}{36}\)

\(=\frac{20}{49}\)

=3/4-3/5+3/7+3/13 / 11/4-11/5+11/7+11/13   +   3/4-3/5+3/7+3/13 / 11/4-11/5+11/7+11/13

=3.1/4-3.1/5+3.1/7+3.1/13 / 11.1/4-11.1/5+11.1/7+11.1/13    +     3.1/4-3.1/5+3.1/7+3.1/13  /  11. 1/4-11.1/5+11.1/7+11.1/13

=3.(1/4-1/5+1/7+1/13) / 11.(1/4-1/5+1/7+1/13)     +   3.(1/4-1/5+1/7+1/13)   /  11.(1/4-1/5+1/7+1/13)

=3/11+3/11

=6/11

Câu 1;

\(\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}\cdot\frac{\frac{3}{4}-\frac{3}{16}-\frac{3}{64}-\frac{3}{256}}{1-\frac{1}{4}-\frac{1}{16}-\frac{1}{64}}+\frac{5}{8}\)

\(=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{2\left(\frac{1}{3}-\frac{1}{7}-\frac{1}{13}\right)}\cdot\frac{3\left(\frac{1}{4}-\frac{1}{16}-\frac{1}{64}-\frac{1}{256}\right)}{4\left(\frac{1}{4}-\frac{1}{16}-\frac{1}{64}-\frac{1}{256}\right)}+\frac{5}{8}\)

\(=\frac{1}{2}\cdot\frac{3}{4}+\frac{5}{8}=\frac{3}{8}+\frac{5}{8}=1\)

Câu 2:

\(\frac{0,75-0,6+\frac{3}{7}+\frac{3}{13}}{2,75-2,2+\frac{11}{7}+\frac{11}{3}}=\frac{\frac{3}{4}-\frac{3}{5}+\frac{3}{7}+\frac{3}{13}}{\frac{11}{4}-\frac{11}{5}+\frac{11}{7}+\frac{11}{3}}=\frac{3\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}{11\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}=\frac{3}{11}\)

Câu 1;

13 −17 −113 23 −27 −213  ·34 −316 −364 −3256 1−14 −116 −164  +58 

=13 −17 −113 2(13 −17 −113 ) ·3(14 −116 −164 −1256 )4(14 −116 −164 −1256 ) +58 

=12 ·34 +58 =38 +

rút gọn tu , bạn ơi

Sửa đề \(\frac{11}{13}\)chứ không phải \(\frac{11}{3}\)

\(\frac{2,75-2,2+\frac{11}{7}+\frac{11}{13}}{0,75-0,6+\frac{3}{7}+\frac{3}{13}}-x-\frac{1}{9}=\frac{2}{3}+\frac{2}{15}+\frac{2}{35}+\frac{2}{63}\)

+) Đặt \(A=\frac{2,75-2,2+\frac{11}{7}+\frac{11}{13}}{0,75-0,6+\frac{3}{7}+\frac{3}{13}}\)

\(A=\frac{\frac{11}{4}-\frac{11}{5}+\frac{11}{7}+\frac{11}{13}}{\frac{3}{4}-\frac{3}{5}+\frac{3}{7}+\frac{3}{13}}\)

\(A=\frac{11\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}{3\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}\)

\(A=\frac{11}{3}\)(1)

+) Đặt \(B=\frac{2}{3}+\frac{2}{15}+\frac{2}{35}+\frac{2}{63}\)

\(B=\frac{2}{1\cdot3}+\frac{2}{3\cdot5}+\frac{2}{5\cdot7}+\frac{2}{7\cdot9}\)

\(B=\frac{2}{2}\left(\frac{1}{1\cdot3}+\frac{1}{3\cdot5}+\frac{1}{5\cdot7}+\frac{1}{7\cdot9}\right)\)

\(B=\frac{2}{2}\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{7}-\frac{1}{9}\right)\)

\(B=\frac{2}{2}\left(1-\frac{1}{9}\right)=1\cdot\frac{8}{9}=\frac{8}{9}\)(2)

Từ (1) và (2) => \(A-x-\frac{1}{9}=B\)

=> \(\frac{11}{3}-x-\frac{1}{9}=\frac{8}{9}\)

=> \(\frac{11}{3}-x=1\)

=> \(x=\frac{11}{3}-1=\frac{8}{3}\)

Vậy x = 8/3

Đặt \(A=\frac{2,75-2,2+\frac{11}{7}+\frac{11}{13}}{0,75-0,6+\frac{3}{7}+\frac{11}{13}}-x-\frac{1}{9}=\frac{2}{3}+\frac{2}{15}\frac{2}{35}+\frac{2}{63}\)

\(\Rightarrow A=\frac{0,55+\frac{11}{7}+\frac{11}{13}}{0,15+\frac{3}{7}+\frac{11}{13}}-x-\frac{1}{9}=\frac{42}{63}+\frac{14}{105}+\frac{6}{105}+\frac{2}{63}\)

\(\Rightarrow A=\frac{\frac{11}{20}+\frac{11}{7}+\frac{11}{13}}{\frac{3}{20}+\frac{3}{7}+\frac{11}{13}}-x-\frac{1}{9}=\frac{44}{63}+\frac{20}{105}\)

\(\Rightarrow A=\frac{\frac{1001}{1820}+\frac{2860}{1820}+\frac{1540}{1820}}{\frac{273}{1820}+\frac{780}{1820}+\frac{1540}{1820}}-x-\frac{1}{9}=\frac{44}{63}+\frac{4}{21}\)

\(\Rightarrow A=\frac{\frac{5401}{1820}}{\frac{2593}{1820}}-x-\frac{1}{9}=\frac{44}{63}+\frac{12}{63}\)

\(\Rightarrow A=\frac{5401}{1820}:\frac{2593}{1820}-x-\frac{1}{9}=\frac{56}{63}\)

\(\Rightarrow A=\frac{5401}{1820}.\frac{1820}{2593}-x-\frac{1}{9}=\frac{8}{9}\)

\(\Rightarrow A=\frac{5401}{2593}-x-\frac{1}{9}=\frac{8}{9}\)

\(\Rightarrow\frac{5401}{2593}-x=\frac{8}{9}+\frac{1}{9}\)

\(\Rightarrow\frac{5401}{2593}-x=1\)

\(\Rightarrow x=\frac{5401}{2593}-1\)

\(\Rightarrow x=\frac{2808}{2593}\)

Vậy \(x=\frac{2808}{2593}\)

Chúc bn học tốt

Nguyen minh Chien

Bạn cố đợi tí nha !

Mình đang làm
 

\(a,\text{ }\frac{\frac{5}{7}-\frac{5}{9}+\frac{5}{11}}{\frac{4}{7}-\frac{4}{9}+\frac{4}{11}}\)

\(=\frac{5\left(\frac{1}{7}-\frac{1}{9}+\frac{1}{11}\right)}{4\left(\frac{1}{7}-\frac{1}{9}+\frac{1}{11}\right)}\)

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

a)\(\frac{\frac{5}{7}-\frac{5}{9}+\frac{5}{11}}{\frac{4}{7}-\frac{4}{7}+\frac{4}{11}}=\frac{5.\left(\frac{1}{7}-\frac{1}{9}+\frac{1}{11}\right)}{4.\left(\frac{1}{7}-\frac{1}{9}+\frac{1}{11}\right)}=\frac{5}{4}\)

\(=\frac{4419}{31603}\)

\(\frac{0,75-0,6+\frac{3}{7}+\frac{3}{13}}{2,75-2,2+\frac{11}{7}+\frac{11}{13}}\)=\(\frac{\frac{3}{4}-\frac{3}{5}+\frac{3}{7}+\frac{3}{13}}{\frac{11}{4}-\frac{11}{5}+\frac{11}{7}+\frac{11}{13}}\)=\(\frac{3.\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}{11.\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}\)=\(\frac{3}{11}\)

mình nghĩ 11/3 ở dưới mẫu phải là 11/13