Đáp án:
a, `A = [(27/25 - 4/50 ) : 4/7 ] : [ 119/36 : ( 17/36 . 1/12 )]`
` = ( 1 : 4/7 ) : ( 119/36 : 17/432 )`
` = 7/4 : 84`
` = 1/48`
b,$\frac{1+\frac{1}{4} }{1-\frac{1}{4}}$:$\frac{1+\frac{1}{8}}{1-\frac{1}{8}}$
= $\frac{\frac{5}{4}}{\frac{3}{4}}$:$\frac{\frac{9}{8}}{\frac{7}{8}}$
`= 35/27`
Học tốt nhé !
