Đáp án + Giải thích các bước giải:
`a, \frac{3}{4}:(\frac{1}{2}:\frac{4}{5})`
`= \frac{3}{4}:(\frac{1}{2}. \frac{5}{4})`
`= \frac{3}{4}: \frac{5}{8}`
`=\frac{3}{4}. \frac{8}{5}`
`= \frac{6}{5}`
`b,( 11/9 : 22/27 ) . 3/4`
`=(11/9 . 27/22). 3/4`
`= 3/2 . 3/4`
`=9/8`
`c, ( 3/5 : 4/7 ) : ( 3/4 : 3 )`
`= (3/5 . 7/4) : (3/4 . 1/3)`
`=21/20 : 1/4`
`=21/20 . 4`
`=21/5`
`d, ( 7/12 . 9/14 ) : ( 1/2 . 6/5 )`
`= 3/8 : 3/5`
`=3/8 . 5/3`
`=5/8`