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

=57

Ai k mk mk se k lai

57 nha ban Ngoc Anh

(575757/424242 + 575757/565656 + 575757/727272) x 18
= (57/42 + 57/56 + 57/72) x 18 
= 57x3/7 + 57x9/28 + 57/4
= 1596/28
= 57

\(\left(\frac{575757}{424242}+\frac{575757}{565656}+\frac{575757}{727272}\right)\cdot18\)

\(=\left(\frac{19}{14}+\frac{57}{56}+\frac{19}{24}\right)\cdot18\)

\(=\left(\frac{228+171+133}{168}\right)\cdot18\)

\(=\frac{532}{168}\cdot18\)

\(=\frac{19}{6}\cdot8\)

\(=\frac{76}{3}\)

 = 57 (chắc chắn đúng)

\(\left(\frac{575757}{424242}+\frac{575757}{565656}+\frac{575757}{727272}\right)\cdot18=\left(\frac{57}{42}+\frac{57}{56}+\frac{57}{72}\right)\cdot18=\frac{57}{42}\cdot18+\frac{57}{56}\cdot18+\frac{57}{72}\cdot18=\frac{171}{7}+\frac{513}{28}+\frac{57}{4}=\frac{684}{28}+\frac{513}{28}+\frac{399}{28}=\frac{1596}{28}=57\)

\(\frac{575757}{424242}+\frac{575757}{565656}+\frac{575757}{727272}=\frac{57\times10101}{42\times10101}+\frac{57\times10101}{56\times10101}+\frac{57\times10101}{72\times10101}\)

\(=\frac{57}{42}+\frac{57}{56}+\frac{57}{72}=57\times\left(\frac{1}{42}+\frac{1}{56}+\frac{1}{72}\right)\)

\(=57\times\left(\frac{1}{6\times7}+\frac{1}{7\times8}+\frac{1}{8\times9}\right)\)

\(=57\times\left(\frac{7-6}{6\times7}+\frac{8-7}{7\times8}+\frac{9-8}{8\times9}\right)\)

\(=57\times\left(\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}\right)\)

\(=57\times\left(\frac{1}{6}-\frac{1}{9}\right)=\frac{19}{6}\)

57 bạn nhé

\(=\left(\frac{57}{42}+\frac{57}{56}+\frac{57}{72}\right)\times18\)

\(=\frac{19}{6}\times18=57\)

= (57/42 +57/56 + 57/72),18

=(1/6.7 +1/7.8 +1/8.9).18.57

=(1/6-1/7 +1/7 -1/8 +1/8-1/9).18.57

=(1/6-1/9) .18 .57

=57.3 - 57.2

=57

\(\frac{575757}{\text{424242}}\)+ \(\frac{575757}{565656}\) + \(\frac{575757}{727272}\) = \(\frac{19}{14}\)+ \(\frac{57}{56}\)+ \(\frac{19}{24}\)

                                                    = \(\frac{25536}{18816}\)+ \(\frac{15162}{18816}\)+ \(\frac{14896}{18816}\)

                                                    =  \(\frac{40698}{18816}\)+ \(\frac{14896}{18816}\)

                                                    = \(\frac{55594}{18816}\)

                                                    = \(\frac{3971}{1344}\)

= 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

\(A=\left(\frac{575757}{424242}+\frac{575757}{565656}+\frac{575757}{727272}\right)\times18\)

\(=\left(\frac{57\times10101}{42\times10101}+\frac{57\times10101}{56\times10101}+\frac{57\times10101}{72\times10101}\right)\times18\)

\(=\left(\frac{57}{42}+\frac{57}{56}+\frac{57}{72}\right)\times18\)

\(=57\left(\frac{1}{42}+\frac{1}{56}+\frac{1}{72}\right)\times18\)

\(=\frac{57}{18}\times18=57\)