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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
\(\frac{575757}{424242}+\frac{575757}{565656}+\frac{575757}{727272}=\frac{57\times10101}{42\times10101}+\frac{57\times10101}{56\times10101}+\frac{57\times10101}{72\times10101}\)
\(=\frac{57}{42}+\frac{57}{56}+\frac{57}{72}=57\times\left(\frac{1}{42}+\frac{1}{56}+\frac{1}{72}\right)\)
\(=57\times\left(\frac{1}{6\times7}+\frac{1}{7\times8}+\frac{1}{8\times9}\right)\)
\(=57\times\left(\frac{7-6}{6\times7}+\frac{8-7}{7\times8}+\frac{9-8}{8\times9}\right)\)
\(=57\times\left(\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}\right)\)
\(=57\times\left(\frac{1}{6}-\frac{1}{9}\right)=\frac{19}{6}\)
\(\frac{575757}{\text{424242}}\)+ \(\frac{575757}{565656}\) + \(\frac{575757}{727272}\) = \(\frac{19}{14}\)+ \(\frac{57}{56}\)+ \(\frac{19}{24}\)
= \(\frac{25536}{18816}\)+ \(\frac{15162}{18816}\)+ \(\frac{14896}{18816}\)
= \(\frac{40698}{18816}\)+ \(\frac{14896}{18816}\)
= \(\frac{55594}{18816}\)
= \(\frac{3971}{1344}\)
= 19/6 tương đương với 3,166666667
Bạn nên sử dụng máy tính đi ạ ^^
= \(\frac{575757}{424242}+\frac{575757}{565656}+\frac{575757}{727272}\)
=\(\frac{57}{42}+\frac{57}{56}+\frac{57}{72}\)
=\(\frac{19}{6}\)
Bài giải :
\(\frac{575757}{424242}\)= \(\frac{57}{45}\)
\(\frac{575757}{565656}\)= \(\frac{57}{56}\)
\(\frac{575757}{727272}\)= \(\frac{57}{72}\)
\(=>\) ( \(\frac{57}{45}\)+ \(\frac{57}{56}\)\(\frac{57}{72}\) ) x \(18\)\(=\)\(57\)
Hk tốt
\(A=\left(\frac{575757}{424242}+\frac{575757}{565656}+\frac{575757}{727272}\right)\times18\)
\(=\left(\frac{57\times10101}{42\times10101}+\frac{57\times10101}{56\times10101}+\frac{57\times10101}{72\times10101}\right)\times18\)
\(=\left(\frac{57}{42}+\frac{57}{56}+\frac{57}{72}\right)\times18\)
\(=57\left(\frac{1}{42}+\frac{1}{56}+\frac{1}{72}\right)\times18\)
\(=\frac{57}{18}\times18=57\)
= \(\left(\frac{57}{42}+\frac{57}{56}+\frac{57}{72}\right)x18\)
= \(\frac{57}{42}x18+\frac{57}{56}x18+\frac{57}{72}x18\)
=\(\frac{57}{7}x3+\frac{57}{28}x9+\frac{57}{4}\)
= \(\frac{57x12}{28}+\frac{57x9}{28}+\frac{57x7}{28}\)
=\(\frac{57x\left(12+9+7\right)}{28}\)
\(=\frac{57x28}{28}\)
=57
Tớ mới học được kết quả đấy có thể các cần bài này
rut gon
= (57/42+57/56+57/72)*18
=19/6*18
=57