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

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

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

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

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

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

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

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

= \(\frac{30}{91}+\frac{54}{63}\)

= \(\frac{30}{91}+\frac{6}{7}\)

= \(\frac{30}{91}+\frac{78}{91}\)

= \(\frac{108}{91}\)

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 !!! 

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

\(=\frac{-6\left(\frac{1}{7}-\frac{1}{13}+\frac{1}{29}\right)}{9\left(\frac{1}{7}-\frac{1}{13}+\frac{1}{29}\right)}=\frac{-6}{9}=-\frac{2}{3}\)

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

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

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

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

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

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

1/12 chứ cháu

Bài 1: 

\(A=\frac{24.47-22}{24+47.23}.\frac{5+\frac{5}{7}+\frac{5}{11}-\frac{5}{13}+\frac{5}{1001}}{6+\frac{6}{7}+\frac{6}{11}-\frac{6}{13}+\frac{6}{1001}}\)\(=\frac{47.23+47-22}{24.47.23}.\frac{5\left(1+\frac{1}{7}+\frac{1}{11.}-\frac{1}{13}+\frac{1}{1001}\right)}{6\left(1+\frac{1}{7}+\frac{1}{11}-\frac{1}{13}+\frac{1}{1001}\right)}\) 

                                                                         \(=\frac{47.23+24}{24+47.23}.\frac{5}{6}\) 

                                                                         \(=1.\frac{5}{6}=\frac{5}{6}\) 

Bài 2: 

\(81^7-27^9-9^{13}=\left(3^4\right)^7-\left(3^3\right)^9-\left(3^2\right)^{13}\) 

                                      \(=3^{28}-3^{27}-3^{26}\) 

                                      \(=3^{22}\left(3^6-3^5-3^4\right)\) 

                                      \(=3^{22}.405\) chia hết cho 405 

 =>đpcm

Tính tất cả ra thì được:

\(=\frac{\frac{973}{60}}{\frac{139}{60}}:\frac{\frac{1255}{221}}{\frac{1506}{221}}+\frac{5858}{5050}\)

\(=\frac{\frac{139}{60}}{\frac{973}{60}}.\frac{\frac{1506}{221}}{\frac{1255}{221}}+\frac{5858}{5050}\)

Tính tử và mẫu dần rồi ra ( phần này dễ mà )

Ta được: ( mình chỉ lấy 2 chữ số phần thập phân thôi )

\(=\frac{1578}{9209}+\frac{5858}{5050}\)

 = 133/100

End 

Ta có \(81.\left(\frac{12-\frac{12}{7}-\frac{12}{289}-\frac{12}{85}}{4-\frac{4}{7}-\frac{4}{289}-\frac{3}{85}}:\frac{5+\frac{5}{13}+\frac{5}{169}+\frac{5}{91}}{6+\frac{6}{13}+\frac{6}{169}+\frac{6}{91}}\right)\)

\(=81.\left(\frac{12.\left(1-\frac{1}{7}-\frac{1}{289}-\frac{1}{85}\right)}{4.\left(1-\frac{1}{7}-\frac{1}{289}-\frac{1}{85}\right)}:\frac{5.\left(1+\frac{1}{13}+\frac{1}{169}+\frac{1}{91}\right)}{6.\left(1+\frac{1}{13}+\frac{1}{169}+\frac{1}{91}\right)}\right)\)

\(=81.\left(\frac{12}{4}:\frac{5}{6}\right)\)

\(=81.\frac{18}{5}\)

\(=291,6\)

\(81\left(\frac{12-\frac{12}{7}-\frac{12}{289}-\frac{12}{85}}{4-\frac{4}{7}-\frac{4}{289}-\frac{4}{85}}:\frac{5+\frac{5}{13}+\frac{5}{169}+\frac{5}{91}}{6+\frac{6}{13}+\frac{6}{159}+\frac{6}{91}}\right)\)

\(=81\left(\frac{12\left(1-\frac{1}{7}-\frac{1}{289}-\frac{1}{85}\right)}{4\left(1-\frac{1}{7}-\frac{1}{289}-\frac{1}{85}\right)}:\frac{5\left(1+\frac{1}{13}+\frac{1}{169}+\frac{1}{91}\right)}{6\left(1+\frac{1}{13}+\frac{2}{169}+\frac{1}{91}\right)}\right)\)

\(=81\left(3\div\frac{5}{6}\right)\)

\(=81.\frac{18}{5}\)

\(=\frac{1458}{5}\)

81.[12(1-1/7-1/289-1/85)/4(1-1/7-1/289-1/85):5(1+1/13+1/169+1/91)/6(1/13+1/169+1/91)

=81.[12/4:5/6]=81.[12/4.6/5]=81.18/5=1458/5