Đáp án:
`x=45/44`
Giải thích các bước giải:
`(1/2 + 1/4 + 1/8 + 1/16) : x = 1/2 + 1/6 + 1/12 +1/20 + ... + 1/132`
`=>` `(1/2 + 1/4 + 1/8 + 1/16) : x = 1/1.2 + 1/2.3 + 1/3.4 +1/4.5 + ... + 1/11.12`
`=>` `(1/2 + 1/4 + 1/8 + 1/16) : x = 1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+...+1/11-1/12`
`=>` `(1/2 + 1/4 + 1/8 + 1/16) : x = 1-(1/2-1/2+1/3-1/3+1/4-1/4+1/5-...-1/11+1/12)`
`=>` `(1/2 + 1/4 + 1/8 + 1/16) : x = 1-1/12`
`=>` `(1/2 + 1/4 + 1/8 + 1/16) : x = 11/12`
`=>` `x=(1/2+1/4+1/8+1/16) : 11/12`
`=>` `x=11/12×(8/16+4/16+2/16+1/16) : 11/12`
`=>` `x=15/16 : 11/12`
`=>` `x=45/44`