`text{Đáp án:}`
`A` `=` `3/11`
`text{Giải thích các bước giải:}`
`A` `=` `(` `0,75` `−` `0,6` `+` `3/7` `+` `3/13` `)` `:` `(` `11/7` `+` `11/13` `+` `2,75` `−` `2,2` `)`
`A` `=` `(3/4−3/5+3/7+3/13)/(11/7+11/13+11/4−11/5)`
`A` `=` $\frac{3 . (\frac{1}{4}−\frac{1}{5}+\frac{1}{7}+\frac{1}{13})}{11 .( \frac{1}{7}+\frac{1}{13}+\frac{1}{4}−\frac{1}{5})}$
`A` `=` $\frac{3 . (\frac{1}{4}+\frac{-1}{5}+\frac{1}{7}+\frac{1}{13})}{11 .( \frac{1}{7}+\frac{1}{13}+\frac{1}{4}+\frac{-1}{5})}$
`A` `=` `3/11`
