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\(\left(\frac{57575757}{42424242}+\frac{57575757}{56565656}+\frac{57575757}{72727272}\right).18\)
\(=\left(\frac{57}{42}+\frac{57}{56}+\frac{57}{72}\right).18\)
\(=57.\left(\frac{1}{42}+\frac{1}{56}+\frac{1}{72}\right)x18\)
\(=57.\left(\frac{1}{6.7}+\frac{1}{7.8}+\frac{1}{8.9}\right)x18\)
\(=57x\left(\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}\right)x18\)
\(=57x\left(\frac{1}{6}-\frac{1}{9}\right)x18\)
=....................................................(Quan trọng nhất là máy tính. Hết thần thái rồi:V
\(\frac{575757}{424242}+\frac{575757}{565656}+\frac{575757}{727272}=\frac{57\times10101}{42\times10101}+\frac{57\times10101}{56\times10101}+\frac{57\times10101}{72\times10101}\)
\(=\frac{57}{42}+\frac{57}{56}+\frac{57}{72}=57\times\left(\frac{1}{42}+\frac{1}{56}+\frac{1}{72}\right)\)
\(=57\times\left(\frac{1}{6\times7}+\frac{1}{7\times8}+\frac{1}{8\times9}\right)\)
\(=57\times\left(\frac{7-6}{6\times7}+\frac{8-7}{7\times8}+\frac{9-8}{8\times9}\right)\)
\(=57\times\left(\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}\right)\)
\(=57\times\left(\frac{1}{6}-\frac{1}{9}\right)=\frac{19}{6}\)
ta có:
575757/424242 = 57/42
575757/565656 = 57/56
575757/727272 = 57/72
suy ra:
(57/42 +57/56 +57/72)x 18 = 57
Bạn xem lại phân số $\frac{103}{303}$ hay $\frac{101}{303}$ vậy?
\(=18\times\left(\frac{37\times10101}{42\times10101}+\frac{37\times10101}{56\times10101}+\frac{37\times10101}{72\times10101}\right)\)
\(=18\times\left(\frac{37}{42}+\frac{37}{56}+\frac{37}{72}\right)\)
\(=666\left(\frac{1}{42}+\frac{1}{56}+\frac{1}{72}\right)\)
\(=666\times\left(\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}\right)\)
\(=666\times\left(\frac{1}{6}-\frac{1}{9}\right)\)
\(=666\times\frac{1}{18}=37\)
\(18\times\left(\frac{373737}{424242}+\frac{373737}{565656}+\frac{373737}{727272}\right)\)
\(=18\times\left(\frac{37}{42}+\frac{37}{56}+\frac{37}{72}\right)\)
\(=18\times\frac{37}{18}\)
\(=37\)
máy tính bạn yêu🤣
ta có 565656/787878 =565656:10101/787878:10101 =56/78
56565656/78787878=56565656:1010101/78787878:1010101=56/78
=> 565656/787878=56565656/78787878
=> 1+565656/787878 -56565656/78787878 +2019 =1+ 2019 +2020
Tích Hộ Với Nha !!!