(  3434/3535 + 3434/6363 + 3434/9999 ) × 55

= (  34/35 + 34/63 + 34/99 ) × 55

= 34 × ( 1/35 + 1/63 + 1/99 ) × 55

=  34 × 3/55 × 55

= 102/55 × 55

= 102

Mình ko chắc lắm đâu nhá

= \(\frac{12}{15}\) +\(\frac{12}{35}\)+\(\frac{12}{63}\)+\(\frac{12}{99}\)

= 12 x (\(\frac{1}{15}\)+\(\frac{1}{35}\)+\(\frac{1}{63}\)+\(\frac{1}{99}\))

= 12 x ( \(\frac{1}{3x5}\)+\(\frac{1}{5x7}\)+\(\frac{1}{7x9}\)+\(\frac{1}{9x11}\))

= 12 x \(\frac{1}{2}\) x    ( \(\frac{1}{3}\)-\(\frac{1}{5}\)+\(\frac{1}{5}\)-\(\frac{1}{7}\)+\(\frac{1}{7}\)-\(\frac{1}{9}\)+\(\frac{1}{9}\)-\(\frac{1}{11}\))

= 6 x (   \(\frac{1}{3}\) -  \(\frac{1}{11}\))

=  6 x \(\frac{8}{33}\)

= \(\frac{48}{33}\)=\(\frac{16}{11}\)

      Nhớ tk nha

lấy tất cả chia cho 1010

\(\frac{1212}{1515}+\frac{1212}{3535}+\frac{1212}{6363}+\frac{1212}{9999}\)

\(=1212.\left(\frac{1}{15.101}+\frac{1}{35.101}+\frac{1}{63.101}+\frac{1}{99.101}\right)\)

\(=12.101.\frac{1}{101}.\left(\frac{1}{15}+\frac{1}{35}+\frac{1}{63}+\frac{1}{99}\right)\)

\(=6.\left(\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}+\frac{2}{9.11}\right)\)

\(=6.\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}\right)\)

\(=6.\left(\frac{1}{3}-\frac{1}{11}\right)\)

\(=6.\left(\frac{11}{33}-\frac{3}{33}\right)\)

\(=6.\frac{8}{33}\)

\(=\frac{16}{11}\)

\(7\cdot x+x:\frac{1}{9}+x=3434\)

\(7\cdot x+x\cdot9+x=3434\)

\(\left(7+9+1\right)x=3434\)

\(17\cdot x=3434\)

\(x=3434:17\)

\(x=202\)

\(7\times x+x:\frac{1}{9}+x=3434\)

\(7\times x+x\times9+x=3434\)

\(\left(7+9\right)\times x+x=3434\)

\(16\times x+x=3434\)

\(17\times x=3434\)

\(x=3434:17\)

\(\Rightarrow x=202\)

\(7\cdot x+x\cdot9+x=3434\)

\(x\cdot\left(7+9+1\right)=3434\)

\(x\cdot17=3434\)

\(x=3434:17=202\)

1616/1515 + 1616/3535 + 1616/6363 + 1616/9999

= 32/21 + 1616/6363 + 1616/9999

= 16/9 + 1616/9999

= 64/33

còn cách khác ko bạn

cách khác nhé:

    \(\frac{1616}{1515}+\frac{1616}{3535}+\frac{1616}{6363}+\frac{1616}{9999}\)

   \(=\frac{16}{15}+\frac{16}{35}+\frac{16}{63}+\frac{16}{99}\)

   \(=16\left(\frac{1}{15}+\frac{1}{35}+\frac{1}{63}+\frac{1}{99}\right)\)

  \(=16\left(\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}\right)\)

  \(=8\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}\right)\)

  \(=8\left(\frac{1}{3}-\frac{1}{11}\right)\)

  \(=\frac{64}{33}\)

Ta có : \(\frac{-3434}{8585}=\frac{x}{5}\)tức là (-3434).5 = 8585x

Vậy \(x=\frac{\left(-3434\right).5}{8585}=-2\).

\(\frac{-3434}{8585}\)=\(\frac{x}{5}\)

                    =\(\frac{-3434}{8585}=\frac{-3434:1717}{8585:1717}=\frac{-2}{5}\)

              Vậy x = -2

học tốt 

#Tan

\(\frac{-3434}{8585}=\frac{x}{5}\)

Thừa số phụ là : \(8585\div5=1717\)

=> \(x=-3434\div1717\)

      \(x=-2\)

     Vậy  \(x=-2\)

\(\frac{1212}{1515}+\frac{1212}{3535}+\frac{1212}{6363}+\frac{1212}{9999}\)

\(=\frac{12}{15}+\frac{12}{35}+\frac{12}{63}+\frac{12}{99}\)

\(=12\cdot\left(\frac{1}{15}+\frac{1}{35}+\frac{1}{63}+\frac{1}{99}\right)\)

\(=12\cdot\frac{4}{33}\)

\(=\frac{16}{11}\)

\(\frac{1212}{1515}+\frac{1212}{3535}+\frac{1212}{6363}+\frac{1212}{9999}\)

\(=\frac{12}{15}+\frac{12}{35}+\frac{12}{63}+\frac{12}{99}\)

\(=12\left(\frac{1}{15}+\frac{1}{35}+\frac{1}{63}+\frac{1}{99}\right)\)

\(=12\left(\frac{1}{3\cdot5}+\frac{1}{3\cdot7}+\frac{1}{7\cdot9}+\frac{1}{9\cdot11}\right)\)

\(=12\cdot\frac{1}{2}\left(\frac{2}{3\cdot5}+\frac{2}{3\cdot7}+\frac{2}{7\cdot9}+\frac{2}{9\cdot11}\right)\)

\(=6\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}\right)\)

\(=6\left(\frac{1}{3}-\frac{1}{11}\right)\)

\(=6\cdot\frac{8}{33}\)

\(=\frac{48}{33}\)

Sorry , mình làm hơi tắt 1 xíu

Ta có : \(12\cdot\left(\frac{1}{15}+\frac{1}{35}+\frac{1}{63}+\frac{1}{99}\right)\)

\(=6\cdot\left(\frac{2}{15}+\frac{2}{35}+\frac{2}{63}+\frac{2}{99}\right)\)

\(=6\cdot\left(\frac{2}{3\cdot5}+\cdot\cdot\cdot+\frac{2}{9\cdot11}\right)\)

\(=6\cdot\left(\frac{1}{3}-\frac{1}{5}+\cdot\cdot\cdot+\frac{1}{9}-\frac{1}{11}\right)\)

\(=6\cdot\left(\frac{1}{3}-\frac{1}{11}\right)\)

\(=6\cdot\frac{8}{33}\)

\(=\frac{16}{11}\)

34345:34343= 11792356 Tick nha thiên bình thân thiện