tính
E=\(\frac{5}{9.13}+\frac{7}{9.25}+\frac{13}{19.25}+\frac{31}{19.39}\)
Những câu hỏi liên quan
\(\frac{-5}{9.13}-\frac{7}{9.25}-\frac{13}{19.25}-\frac{31}{19.69}\)
Tính nhanh:
\(\frac{-5}{9.13}-\frac{7}{9.25}-\frac{-13}{19.25}-\frac{31}{19.69}\)
\(ĐặtA=\frac{-5}{9.13}-\frac{7}{9.25}-\frac{13}{19.25}-\frac{31}{19.69}\)
\(\frac{-1}{2}.A=\frac{5}{13.18}+\frac{7}{18.25}+\frac{13}{25.38}+\frac{31}{38.69}\)
\(\frac{-1}{2}.A=\frac{1}{13}-\frac{1}{18}+\frac{1}{18}-\frac{1}{25}+\frac{1}{25}-\frac{1}{38}+\frac{1}{38}-\frac{1}{69}\)
\(\frac{-1}{2}.A=\frac{1}{13}-\frac{1}{69}\)
\(\frac{-1}{2}.A=\frac{56}{897}\)
\(A=\frac{56}{897}:\left(-\frac{1}{2}\right)\)
\(A=\frac{56}{897}.\left(-2\right)\)
\(A=\frac{-112}{897}\)
Đề của bn sai nên mk sửa lại
Ủng hộ mk nha ^_^
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Đặt \(A=\frac{-5}{9.13}-\frac{7}{9.25}-\frac{-13}{19.25}-\frac{31}{19.69}\)
\(\frac{A}{2}=\frac{-5}{18.13}-\frac{7}{18.25}-\frac{-13}{38.25}-\frac{31}{38.69}\)
Đến đây tự làm
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Tính
(\(\frac{112}{13.20}+\frac{112}{20.27}+\frac{112}{27.34}+...+\frac{112}{62.64}\))
: (\(\frac{-5}{9.13}-\frac{7}{9.25}-\frac{13}{19.25}-\frac{31}{19.69}\)
= 112.[1 / 13.20 + 1 / 20.27 + ...... + 1 / 62.64]
= 112. [ 1/7 . ( 1/13 - 1/20 ) + 1/7 . ( 1/20 - 1/27 ) + ..... + 1/62.64 ]
= 112. [ 1/7. 1/13 - 1/7 - 1/20 + 1/7 . 20 - 1/7 . 1/27 + ..... + 1/ 62.64 ]
= 112. [ 1/7 . 1/13 + 1/ 62.64]
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\(\left(\frac{112}{13.20}+\frac{112}{20.27}+\frac{112}{27.34}+....+\frac{112}{62.69}\right):\left(-\frac{5}{9.13}-\frac{7}{9.25}-\frac{13}{19.25}-\frac{31}{19.69}\right)\)
Tính hợp lí:
\(C=\left(\frac{112}{13.20}+\frac{112}{20.27}+\frac{112}{27.34}+...+\frac{112}{62.69}\right):\left(-\frac{5}{9.13}-\frac{7}{9.25}-\frac{13}{19.25}-\frac{31}{19.69}\right)\)
Tình hợp lí
C=(11213.20 +11220.27 +11227.34 +...+11262.69 ):(−59.13 −79.25 −1319.25 −3119.69 )
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B=\(\left(\frac{112}{13.20}+\frac{112}{20.27}+\frac{112}{27.34}+.........+\frac{112}{62.69}\right):\left(\frac{-5}{9.13}-\frac{7}{9.25}-\frac{13}{19.25}-\frac{31}{19.69}\right)\)
\(=\left[16\cdot\left(\dfrac{1}{13}-\dfrac{1}{20}+\dfrac{1}{20}-\dfrac{1}{27}+...+\dfrac{1}{62}-\dfrac{1}{69}\right)\right]:\dfrac{-112}{897}\)
\(=16\left(\dfrac{1}{13}-\dfrac{1}{69}\right)\cdot\dfrac{-897}{112}\)
\(=-\dfrac{897}{7}\cdot\dfrac{56}{897}=-8\)
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Tính \(A=\left(\frac{112}{13.20}+\frac{112}{20.27}+...+\frac{112}{62.69}\right)\div\)\(\left(\frac{-5}{9.13}-\frac{7}{9.25}-\frac{13}{19.25}-\frac{31}{19.69}\right)\)
Ta có: \(\left(\frac{112}{13.20}+\frac{112}{20.27}+...+\frac{112}{62.69}\right)\)
=\(\left(\frac{112}{13}-\frac{112}{20}+\frac{112}{20}-\frac{112}{27}+...+\frac{112}{62}-\frac{112}{69}\right)\)
112 là tử chung
=>\(112\cdot\left(\frac{1}{13}-\frac{1}{20}+\frac{1}{20}-\frac{1}{27}+...+\frac{1}{62}-\frac{1}{69}\right)\)
Rút gọn các phân số cho nhau, ta còn:
\(112.\left(\frac{1}{13}-\frac{1}{69}\right)\)=\(112\cdot\frac{56}{897}=\frac{6272}{897}\)(1)
Ta có: \(\left(\frac{-5}{9\cdot13}-\frac{7}{9\cdot25}-\frac{13}{19\cdot25}-\frac{31}{19\cdot69}\right)\)=\(\left(-\frac{24}{325}-\frac{122}{32775}\right)\)=\(\left(-\frac{1322}{17043}\right)\)(2)
(1);(2) => \(A=\)\(\frac{6272}{897}\)\(:\left(-\frac{1322}{17043}\right)\)\(\)\(=\)\(-\frac{59584}{661}\)
C
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Tìm x, biết:
\(\left(\frac{14098}{13.20}+\frac{14098}{20.27}+\frac{14098}{27.34}+...+\frac{14098}{62.69}\right)x=\frac{2013}{2}\left(-\frac{5}{9.13}-\frac{7}{9.25}-\frac{13}{19.25}-\frac{31}{19.69}\right)\)
\(\left(\frac{112}{13.20}+\frac{112}{20.27}+\frac{112}{27.34}+...+\frac{112}{62.69}\right)\) \(:\left(-\frac{5}{9.13}-\frac{7}{9.25}-\frac{13}{19.25}-\frac{31}{19.69}\right)\)