Đáp án:
Giải thích các bước giải:
` 2x``-``1/2``-``1/6``-``1/12` - ... - `1/(49.50)` `=` `7` `-` `1/50` + `x`
` 2x`-`x``-`(`1/2``+``1/6``+``1/12` + ... + `1/(49.50)`)`=``7` `-` `1/50`
`1x` `-`(`1/1.2``+``1/2.3``+``1/3.4` + ... + `1/(49.50)`)`=``7` `-` `1/50`
`1x` `-`(`1``-``1/2``+``1/2``-``1/3``+``1/3``-``1/4``+``...``+``1/49``-``1/50``=``7` `-` `1/50`
`1x` `-``(1``-``1/50)``=``7` `-` `1/50`
`1x` `=` `8``-``2/50`
`⇒` `x`=`(199)/(25)`