1. Sắp xếp dãy phân số \(\frac{1}{2};\frac{1}{4};\frac{1}{6};\;\frac{1}{5}\;\) theo thứ tự từ tăng dần.

2. Tìm x, biết:

a) \(x - \frac{3}{4} = \frac{{ - 2}}{3}\)

b) \(\frac{{ - 3}}{4}:x + 1 = \frac{{ - 2}}{3}\)

c) \(\frac{{x - 3}}{{12}} = \frac{{ - 5}}{4}\)

1. Vì 2 < 4 < 5 < 6 nên \(\frac{1}{2} > \frac{1}{4} > \frac{1}{5} > \;\frac{1}{6}\)

2. 

a) \(x - \frac{3}{4} = \frac{{ - 2}}{3}\)

\(\begin{array}{l}x = \frac{{ - 2}}{3} + \frac{3}{4}\\x = \frac{1}{{12}}\end{array}\)

Vậy \(x = \frac{1}{{12}}\).

b) \(\frac{{ - 3}}{4}:x + 1 = \frac{{ - 2}}{3}\)

\(\begin{array}{l}\frac{{ - 3}}{4}:x = \frac{{ - 2}}{3} - 1\\\frac{{ - 3}}{4}:x = \frac{{ - 5}}{3}\\x = \frac{{ - 3}}{4}:\frac{{ - 5}}{3}\\x = \frac{9}{{20}}\end{array}\)

Vậy \(x = \frac{9}{{20}}\).

c) \(\frac{{x - 3}}{{12}} = \frac{{ - 5}}{4}\)

\(\begin{array}{l}\left( {x - 3} \right).4 =  - 5.12\\4\left( {x - 3} \right) =  - 60\\x - 3 =  - 60:4\\x - 3 =  - 15\\x =  - 15 + 3\\x =  - 12\end{array}\)

Vậy \(x =  - 12\).