Đáp án:
`(1xx3xx5+2xx6xx10+4xx12xx20)/(1xx5xx7+2xx10xx14+4xx20xx28)>3/8`.
Giải thích các bước giải:
`(1xx3xx5+2xx6xx10+4xx12xx20)/(1xx5xx7+2xx10xx14+4xx20xx28`
`=(1xx3xx5+2xx6xx2xx5+4xx12xx5xx4)/(1xx5xx7+2xx5xx2xx14+4xx4xx5xx28)`
`=(5xx(1xx3+4xx6+12xx16))/(5xx(1xx7+4xx14+16xx28)`
`=(1xx3+4xx6+12xx16)/(1xx7+4xx14+16xx28`
`=(1xx3+4xx2xx3+3xx4xx16)/(1xx7+4xx7xx2+16xx7xx4`
`=(3xx(1+2xx4+4xx16))/(7xx(1+2xx4+4xx16)`
`=3/7xx(1+2xx4+4xx16)/(1+2xx4+4xx16)`
`=3/7xx1`
`=3/7>3/8`
Vậy `(1xx3xx5+2xx6xx10+4xx12xx20)/(1xx5xx7+2xx10xx14+4xx20xx28)>3/8`.