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28 tháng 5 2019

a)  4 + 4 73 − 4 115 5 + 5 73 − 1 23 = 4 1 + 1 73 − 1 115 5 1 + 1 73 − 1 115 = 4 5

b)  5 22 + 3 13 − 1 2 4 13 − 2 11 + 3 2 = 65 + 66 − 143 286 88 − 52 + 429 286 = − 12 286 465 286 = − 4 155

26 tháng 3 2020

Mk chỉ biết câu a thôi

a) \(\frac{\frac{5}{7}+\frac{5}{9}-\frac{5}{11}}{\frac{15}{7}+\frac{15}{9}-\frac{15}{11}}\)

\(\frac{5\cdot\left(\frac{1}{7}+\frac{1}{9}-\frac{1}{11}\right)}{15\cdot\left(\frac{1}{7}+\frac{1}{9}-\frac{1}{11}\right)}\)

\(\frac{5}{15}\)

\(\frac{1}{3}\)

Chúc bạn học tốt

20 tháng 3 2020

\(A=\frac{3}{4}-\left(\frac{5}{2}+\frac{5}{3}\right)+\left(\frac{-1}{3}\right)^2\)

\(\Rightarrow A=\frac{3}{4}-\left(\frac{15}{6}+\frac{10}{6}\right)+\frac{1}{9}\)

\(\Rightarrow A=\frac{3}{4}-\frac{25}{6}+\frac{1}{9}\)

\(\Rightarrow A=\frac{18}{24}-\frac{100}{24}+\frac{1}{9}\)

\(\Rightarrow A=\frac{-82}{24}+\frac{1}{9}\)

\(\Rightarrow A=\frac{-41}{12}+\frac{1}{9}=\frac{-123}{36}+\frac{4}{36}=\frac{-119}{36}\)

Vậy A=\(\frac{-119}{36}\)

b)\(B=\frac{-11}{19}.\frac{4}{13}+\frac{-11}{13}.\frac{15}{19}+\frac{11}{13}\)

\(\Rightarrow B=\frac{-11}{19}.\frac{4}{13}+\frac{11}{13}.\left(\frac{-15}{19}+1\right)\)

\(\Rightarrow B=\frac{-11}{19}.\frac{4}{13}+\frac{11}{13}.\frac{4}{19}\)

\(\Rightarrow B=\frac{-11}{13}.\frac{4}{19}+\frac{11}{13}.\frac{4}{19}=\frac{4}{19}.\left(\frac{-11}{13}+\frac{11}{13}\right)=\frac{4}{19}.\frac{0}{13}=\frac{4}{19}.0=0\)

Vậy B=0

Chúc bn học tốt

Bài 1:Tính (tính nhanh nếu có thể)\(\frac{25}{42}-\frac{20}{63}\)                                  \(\frac{9}{50}-\frac{13}{75}-\frac{1}{6}\)                                       \(\left(\frac{3}{4}:\frac{2}{3}\right):\frac{3}{5}\)\(-\frac{21}{10}+\frac{21}{10}.\frac{3}{4}-\frac{3}{4}\)                            \(\frac{-2}{3}+2.\left(-\frac{2}{3}\right).3^2-3\)                     ...
Đọc tiếp

Bài 1:Tính (tính nhanh nếu có thể)

\(\frac{25}{42}-\frac{20}{63}\)                                  \(\frac{9}{50}-\frac{13}{75}-\frac{1}{6}\)                                       \(\left(\frac{3}{4}:\frac{2}{3}\right):\frac{3}{5}\)

\(-\frac{21}{10}+\frac{21}{10}.\frac{3}{4}-\frac{3}{4}\)                            \(\frac{-2}{3}+2.\left(-\frac{2}{3}\right).3^2-3\)                       \(\frac{21}{25}.\frac{11}{9}.\frac{5}{7}\)

\(\frac{5}{23}.\frac{17}{26}+\frac{5}{23}.\frac{9}{26}\)

Bài 2:Tính các tổng sau bằng phương pháp hợp lí nhất

\(A=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{49.50}\)

\(B=\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}+...+\frac{2}{37.39}\)

\(C=\frac{3}{4.7}+\frac{3}{7.10}+\frac{3}{10.13}+...+\frac{3}{73.76}\)

\(D=\frac{5}{10.11}+\frac{5}{11.12}+\frac{5}{12.13}+...+\frac{5}{99.100}\)

Bài 3:Tính giá trị biểu thức

\(\frac{\frac{5}{7}+\frac{5}{9}-\frac{5}{11}}{\frac{15}{7}+\frac{15}{9}-\frac{15}{11}}\)                                                      \(\frac{4+\frac{4}{73}-\frac{4}{115}}{5+\frac{5}{73}-\frac{1}{23}}\)

0
17 tháng 4 2017

\(A=11\dfrac{3}{13}-\left(2\dfrac{4}{7}+5\dfrac{3}{13}\right)\)

\(A=11\dfrac{3}{13}-5\dfrac{3}{13}-2\dfrac{4}{7}\)

\(A=6-2\dfrac{4}{7}\)

\(A=5\dfrac{7}{7}-2\dfrac{4}{7}\)

\(A=3\dfrac{3}{7}\)

\(B=\left(6\dfrac{4}{9}+3\dfrac{7}{11}\right)-4\dfrac{4}{9}\)

\(B=\left(6\dfrac{4}{9}-4\dfrac{4}{9}\right)+3\dfrac{7}{11}\)

\(B=2+3\dfrac{7}{11}\)

\(B=5\dfrac{7}{11}\)

\(C=\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}-\dfrac{9}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{-5}{7}.\left(\dfrac{2}{11}+1\right)-\dfrac{9}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{-5}{7}.\dfrac{13}{11}-\dfrac{9}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{-65}{77}-\dfrac{9}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{4}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{160}{11}\)

\(D=0,7.2\dfrac{2}{3}.20.0,375.\dfrac{5}{28}\)

\(D=\dfrac{7}{10}.\dfrac{8}{3}.20.\dfrac{375}{1000}.\dfrac{5}{28}\)

\(D=\dfrac{7}{28}=\dfrac{5}{2}\)

\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right)\left(\dfrac{1}{3}-0,25-\dfrac{1}{12}\right)\)

\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right)\left(\dfrac{1}{3}-\dfrac{1}{4}-\dfrac{1}{12}\right)\)

\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right)\left(\dfrac{1}{12}-\dfrac{1}{12}\right)\)

\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right).0\)

\(\Rightarrow E=0\)

23 tháng 2 2021

mik ko hieu lam

11 tháng 3 2018

a) \(\frac{\frac{5}{7}+\frac{5}{9}-\frac{5}{11}}{\frac{15}{7}+\frac{15}{9}-\frac{15}{11}}=\frac{\frac{5}{7}+\frac{5}{9}-\frac{5}{11}}{\frac{\left(10+5\right)}{7}+\frac{\left(10+5\right)}{9}-\frac{\left(10+5\right)}{11}}\)

\(=\frac{\frac{5}{7}+\frac{5}{9}-\frac{5}{11}}{\left(\frac{10}{7}+\frac{5}{7}\right)+\left(\frac{10}{9}+\frac{5}{9}\right)-\left(\frac{10}{11}+\frac{5}{11}\right)}=\frac{0}{\frac{10}{7}+\frac{10}{9}-\frac{10}{11}}=0\)

b) \(\frac{4+\frac{4}{73}-\frac{4}{115}}{5+\frac{5}{73}-\frac{1}{23}}=\frac{4+\frac{4}{73}-\frac{4}{115}}{5+\frac{1}{73}+\frac{4}{73}-\frac{5}{115}}=\frac{4+\frac{4}{73}-\frac{4}{115}}{5+\frac{1}{73}+\frac{4}{73}-\frac{4}{115}+\frac{1}{115}}\)

\(=\frac{4}{5+\frac{1}{73}-\frac{1}{115}}=0\)

11 tháng 3 2018

tth làm dài quá, làm gọn hơn nè

a, \(\frac{\frac{5}{7}+\frac{5}{9}-\frac{5}{11}}{\frac{15}{7}+\frac{15}{9}-\frac{15}{11}}=\frac{5\left(\frac{1}{7}+\frac{1}{9}-\frac{1}{11}\right)}{15\left(\frac{1}{7}+\frac{1}{9}-\frac{1}{11}\right)}=\frac{5}{15}=\frac{1}{3}\)

b, \(\frac{4+\frac{4}{73}-\frac{4}{115}}{5+\frac{5}{73}-\frac{1}{23}}=\frac{4+\frac{4}{73}-\frac{4}{115}}{5+\frac{5}{73}-\frac{5}{115}}=\frac{4\left(1+\frac{1}{73}-\frac{1}{115}\right)}{5\left(1+\frac{1}{73}-\frac{1}{115}\right)}=\frac{4}{5}\)

26 tháng 10 2018

a)\(A=\frac{3^{10}.11+3^{10}.5}{3^9.2^4}=\frac{3^{10}\left(11+5\right)}{3^9.2^4}=\frac{3.16}{2^4}=\frac{3.2^4}{2^4}=3\)

b)\(B=\frac{2^{10}.13+2^{10}.65}{2^8.104}=\frac{2^{10}\left(13+65\right)}{2^8.2^3.13}=\frac{2^{10}.78}{2^{11}.13}=3\)

c)\(C=\frac{4^9.36+64^4}{16^4.100}=\frac{2^{18}.2^2.3^2+2^{24}}{2^{16}.2^2.5^2}=\frac{2^{20}\left(3^2+2^4\right)}{2^{18}.5^2}=\frac{2^2.25}{25}=4\)