\(\frac{5.8+10.24+15.32}{10.16+20.48+30.64}\)=\(\frac{40+40.6+40.12}{160+160.6+160.12}\)

                                                 =\(\frac{40.\left(1+6+12\right)}{160.\left(1+6+12\right)}\)

                                                 =\(\frac{1}{4}\)

hok tốt

phương anh##

31.36/61.28

5.8 + 10.24 + 15.32 / 10.16 + 20.48 + 30.64

= 5.8 + 10.24 + 15.32 / 5.8.2.2 + 10.24.2.2 + 15.32.2.2

= 5.8 + 10.24 + 15.32 / 5.8.2.2 + 10.24.2.2 + 15.32.2.2

= 1 / 2.2.2.2.2.2

= 1/64

các bạn ơi giúp mình bai này nhé : Tích của 2 phân số là 2/5 .Nếu ta thêm vào thừa số thứ hai 3 đơn vị thì được tích là 28/15.Tìm hai phân số. 

Nhanh lên các bạn ơi

\(A=\frac{4}{2.5}+\frac{4}{5.8}+\frac{4}{8.11}+...+\frac{4}{65.68}\)

\(A=\frac{4}{3}.\left(\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+...+\frac{3}{65.68}\right)\)

\(A=\frac{4}{3}.\left(\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...+\frac{1}{65}-\frac{1}{68}\right)\)

\(A=\frac{4}{3}.\left[\frac{1}{2}+\left(\frac{1}{5}-\frac{1}{5}\right)+\left(\frac{1}{8}-\frac{1}{8}\right)+...+\left(\frac{1}{65}-\frac{1}{65}\right)-\frac{1}{68}\right]\)

\(A=\frac{4}{3}.\left[\frac{1}{2}-\frac{1}{68}\right]\)

\(A=\frac{4}{3}.\frac{33}{68}\)

\(A=\frac{11}{17}\)

~ Hok tốt ~

\(A=\frac{4}{3}\left(\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+....+\frac{1}{65}-\frac{1}{68}\right)\)

     \(=\frac{4}{3}\left(\frac{1}{2}-\frac{1}{68}\right)\)

       \(=\frac{4}{3}\times\frac{33}{68}=\frac{11}{17}\)

39,52-23,48+20,48-26,52

=10

Đáp số: 10

bang 10

39,52 - 23,48 + 20,48 - 26,52

= ( 39,52 - 26,52 ) + ( 23,48 - 20,48 )

= 13 + 3

= 16

= 1/2 - 1/5 + 1/5 - 1/8 + 1/8 - 1/11 + .... + 1/29 - 1/32

= 1/2 - 1/32

= ..... ( tự bấm máy tính nhé )

Ta có: \(E=\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+....+\frac{1}{29}-\frac{1}{32}\)

     \(\Rightarrow E=\frac{1}{2}-\frac{1}{32}\)

     \(\Rightarrow E=\frac{16-1}{32}=\frac{15}{32}\)

 Vậy \(E=\frac{15}{32}\)

E=5-2/2×5 + 8-5/5×8+11-8/8×11+.....+32-29/29×32

E=1/2-1/5+1/5-1/8+1/8-1/11+......+1/29-1/32

E=1/2-1/32

E=15/32

\(\frac{4}{2\cdot5}\)+\(\frac{4}{5\cdot8}\)+\(\frac{4}{8\cdot11}\)+.......+\(\frac{4}{8\cdot83}\)=\(\frac{4}{3}\) (\(\frac{3}{2\cdot5}\)+\(\frac{3}{5\cdot8}\) +......+\(\frac{3}{80\cdot83}\) )

=\(\frac{4}{3}\) (\(\frac{1}{2}\) -\(\frac{1}{5}\) +\(\frac{1}{5}\) -\(\frac{1}{8}\) +..........+\(\frac{1}{80}\) -\(\frac{1}{83}\) )

=\(\frac{4}{3}\) (\(\frac{1}{2}\) -\(\frac{1}{83}\) )

=\(\frac{4}{3}\)*\(\frac{81}{166}\) 

=\(\frac{54}{83}\)