bn thiếu đề

x:2 +x:4x6 +x :2x4 = ?

=> x:2+x:24+x:8 = ?

=> x:(2+24+8)  =?

=> x:34  = ?

(đề bài thiếu hả bạn)

`(2/(2xx4)+2/(4xx6)+2/(6xx8)+2/(8xx10))xxy=1/3`

`=>(1/2-1/4+1/4-1/6+1/6-1/8+1/8-1/10)xxy=1/3`

`=>(1/2-1/10)xxy=1/3`

`=>(5/10-1/10)xxy=1/3`

`=>4/10xxy=1/3`

`=>2/5xxy=1/3`

`=>y=1/3:2/5`

`=>y=1/3xx5/2`

`=>y=5/6`

ax4=1/2-1/4+1/4-1/6+1/6+1/8+.......+1/16-1/18+1/18+1/20

ax4  =1/2-1/20

 ax4 =9/20

   a=9/20:4

   a=9/80

THANKS

A=\(\frac{2}{2x4}+\frac{2}{4x6}+.........+\frac{2}{2014x2016}\)

=\(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+.............+\frac{1}{2014}-\frac{1}{2016}\)

=\(\frac{1}{2}-\frac{1}{2016}\)

=\(\frac{1008}{2016}-\frac{1}{2016}\)

=\(\frac{1007}{2016}\)

mình nghĩ nguyễn hung phat làm đúng sồi

\(\left(\frac{1}{2.4}+\frac{1}{4.6}+\frac{1}{6.8}+...+\frac{1}{18.20}\right).10-x=0\)

\(2\left(\frac{2}{2.4}+\frac{2}{4.6}+\frac{2}{6.8}+...+\frac{2}{18.20}\right).10-x=0\)

\(2\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+...+\frac{1}{18}-\frac{1}{20}\right).10-x=0\)

\(2\left(\frac{1}{2}-\frac{1}{20}\right).10-x=0\)

\(2.\frac{9}{20}.10-x=0\)

\(9-x=0\)

\(x=9-0\)

\(x=9\)

1 Phần 2 x(4x-6)=