\(P=\frac{6}{7}.\frac{8}{13}+\frac{6}{9}.\frac{9}{7}-\frac{3}{13}.\frac{6}{7}\)

\(P=\frac{6}{7}.\frac{8}{13}+\frac{6}{7}-\frac{3}{13}.\frac{6}{7}\)

\(P=\frac{6}{7}.\left(\frac{8}{13}+1-\frac{3}{13}\right)\)

\(P=\frac{6}{7}.\frac{18}{13}\)

\(P=\frac{108}{91}\)

\(\frac{6}{7}.\frac{8}{13}+\frac{6}{9}.\frac{9}{7}-\frac{3}{13}.\frac{6}{7}\)

= \(\frac{6}{7}.\left(\frac{8}{13}-\frac{3}{13}\right)+\frac{6}{9}.\frac{9}{7}\)

= \(\frac{6}{7}.\frac{5}{13}+\frac{54}{63}\)

= \(\frac{30}{91}+\frac{54}{63}\)

= \(\frac{30}{91}+\frac{6}{7}\)

= \(\frac{30}{91}+\frac{78}{91}\)

= \(\frac{108}{91}\)

Ta có : 

\(P=\frac{6}{7}.\frac{8}{13}+\frac{6}{9}.\frac{9}{7}-\frac{3}{13}.\frac{6}{7}\)

\(P=\frac{6}{7}.\frac{8}{13}+\frac{6}{7}-\frac{3}{13}.\frac{6}{7}\)

\(P=\frac{6}{7}.\frac{8}{13}+\frac{6}{7}.\frac{13}{13}-\frac{3}{13}.\frac{6}{7}\)

\(P=\frac{6}{7}.\left(\frac{8}{13}+\frac{13}{13}-\frac{3}{13}\right)\)

\(P=\frac{6}{7}.\frac{18}{13}\)

\(P=\frac{108}{91}\)

Tk mk nha !!! 

kb với em với

108/91

\(A=21\frac{4}{11}-\left(1\frac{3}{5}+7\frac{4}{11}\right)\)

\(A=\frac{235}{11}-\left(\frac{8}{5}+\frac{81}{11}\right)\)

\(A=\left(\frac{235}{11}-\frac{81}{11}\right)+\frac{8}{5}\)

\(A=\frac{154}{11}+\frac{8}{5}\)

\(\Rightarrow A=\frac{78}{5}\)

\(B=\left(7\frac{8}{9}+2\frac{3}{13}\right)-\left(4\frac{8}{9}-7\frac{10}{13}\right)\)

\(B=\left(\frac{71}{9}+\frac{29}{13}\right)-\left(\frac{44}{9}-\frac{101}{13}\right)\)

\(B=\left(\frac{71}{9}-\frac{44}{9}\right)+\left(\frac{29}{13}-\frac{101}{13}\right)\)

\(B=\frac{27}{9}+\frac{-72}{13}\)

\(B=3+\frac{-72}{13}\)

\(\Rightarrow B=\frac{-33}{13}\)

P/s: Hoq chắc :v

\(C=\frac{-3}{5}+\frac{2}{7}+\frac{-3}{7}.\frac{3}{5}+\frac{-3}{7}\)

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

\(C=0.\frac{-4}{7}\)

\(C=0\)

\(M=\frac{17}{5}\cdot\frac{-31}{125}\cdot\frac{1}{2}\cdot\frac{10}{17}\cdot\frac{-1}{2^3}\)

\(M=\frac{17}{5}\cdot\frac{-31}{125}\cdot\frac{1}{2}\cdot\frac{10}{7}\cdot\frac{-1}{8}\)

\(M=\left(\frac{17}{5}\cdot\frac{10}{17}\cdot\frac{1}{2}\right)\cdot\frac{-31}{125}\cdot\frac{-1}{8}\)

\(M=1\cdot\frac{31}{1000}=\frac{31}{1000}\)

\(P=\frac{6}{7}\cdot\frac{8}{13}+\frac{6}{9}\cdot\frac{9}{7}-\frac{3}{13}\cdot\frac{6}{7}=\frac{6}{7}\cdot\frac{8}{13}+\frac{6}{7}\cdot1-\frac{3}{13}\cdot\frac{6}{7}\)

\(=\frac{6}{7}\left(\frac{8}{13}+1-\frac{3}{13}\right)=\frac{6}{7}\left(\frac{8}{3}+\frac{13}{13}-\frac{3}{13}\right)=\frac{6}{7}\cdot\frac{18}{13}=\frac{108}{91}\)

\(\frac{\frac{6}{7}-\frac{6}{9}+\frac{6}{11}-\frac{6}{13}}{\frac{8}{7}-\frac{8}{9}+\frac{8}{11}-\frac{8}{13}}\)

=\(\frac{6.\left(\frac{1}{7}-\frac{1}{9}+\frac{1}{11}-\frac{1}{13}\right)}{8.\left(\frac{1}{7}-\frac{1}{9}+\frac{1}{11}-\frac{1}{13}\right)}\)

=\(\frac{6}{8}\)

=\(\frac{3}{4}\)

có z ko tính đk s p hỏi

tính tử òi tính mẫu òi tính cả thế nhé 

ko biết thì hỏi
muốn giỏi phải hok

\(E=\frac{6\left(\frac{1}{7}-\frac{1}{9}+\frac{1}{11}-\frac{1}{13}\right)}{8\left(\frac{1}{7}-\frac{1}{9}+\frac{1}{11}-\frac{1}{13}\right)}=\frac{6}{8}=\frac{3}{4}\)

12/13-2/7-8/13+6/13-5/7=1

\(\frac{12}{13}-\frac{2}{7}+\frac{8}{13}+\frac{6}{13}-\frac{5}{7}\)

\(=\left(\frac{12}{13}+\frac{8}{13}+\frac{6}{13}\right)-\left(\frac{2}{7}+\frac{5}{7}\right)\)

\(=\frac{26}{13}-\frac{7}{7}\)

\(=2-1\)

\(=1\)

\(\frac{12}{13}-\frac{2}{7}+\frac{8}{13}+\frac{6}{13}-\frac{5}{7}\)

\(=\left(\frac{12}{13}+\frac{8}{13}+\frac{6}{13}\right)-\left(\frac{2}{7}+\frac{5}{7}\right)\)

\(=\left(\frac{12+8+6}{13}\right)-\frac{7}{7}\)

\(=\frac{26}{13}-1\)

\(=2-1\)

\(=1\)

a: \(=-9+\left\{-52:9\right\}=-9+\dfrac{-52}{9}=-\dfrac{133}{9}\)

b: \(=\dfrac{17}{7}+\left(\dfrac{-76}{63}\right):15\)

\(=\dfrac{17}{7}-\dfrac{76}{63}\cdot\dfrac{1}{15}=\dfrac{317}{135}\)

e: \(=\dfrac{-5}{13}\cdot\dfrac{7}{3}-\dfrac{2}{7}\cdot\dfrac{8}{13}+\dfrac{5}{13}\cdot\dfrac{1}{7}\)

\(=\dfrac{5}{13}\left(-\dfrac{7}{3}+\dfrac{1}{7}\right)-\dfrac{2}{7}\cdot\dfrac{8}{13}\)

\(=\dfrac{5}{13}\cdot\dfrac{-46}{21}-\dfrac{16}{91}=\dfrac{-278}{273}\)

đặt 6 ở tử làm thừa số chung và 8 ở mẫu làm thừa số chung.rút gọn ta được kq là 6/8=3/4