Đáp án:
$\begin{array}{l}
1)a)\\
\dfrac{3}{2} + \dfrac{1}{4}.\dfrac{8}{3} - \left( { - \dfrac{1}{2}} \right)\\
= \dfrac{3}{2} + \dfrac{2}{3} + \dfrac{1}{2}\\
= \dfrac{4}{2} + \dfrac{2}{3}\\
= 2 + \dfrac{2}{3}\\
= \dfrac{8}{3}\\
2)\dfrac{{ - 5}}{8} - \dfrac{4}{9}.\dfrac{3}{4} - \left| {\dfrac{{ - 1}}{4}} \right|\\
= \dfrac{{ - 5}}{8} - \dfrac{1}{3} - \dfrac{1}{4}\\
= \dfrac{{ - 5.3 - 8 - 6}}{{24}}\\
= \dfrac{{ - 29}}{{24}}\\
3) - 1\dfrac{1}{3} + \dfrac{1}{3} - \left( {\dfrac{{ - 1}}{4}} \right)\\
= - \left( {1 + \dfrac{1}{3}} \right) + \dfrac{1}{3} + \dfrac{1}{4}\\
= - 1 - \dfrac{1}{3} + \dfrac{1}{3} + \dfrac{1}{4}\\
= - 1 + \dfrac{1}{4}\\
= - \dfrac{3}{4}\\
B2)\\
a)\dfrac{2}{3}x - \dfrac{1}{4} = - 2\\
\Rightarrow \dfrac{2}{3}x = - 2 + \dfrac{1}{4}\\
\Rightarrow \dfrac{2}{3}x = \dfrac{{ - 7}}{4}\\
\Rightarrow x = \dfrac{{ - 7}}{4}.\dfrac{3}{2}\\
\Rightarrow x = \dfrac{{ - 21}}{8}\\
\text{Vậy}\,x = \dfrac{{ - 21}}{8}\\
2)\dfrac{3}{4}x + \dfrac{2}{3} = {\left( { - 2} \right)^2}.\dfrac{1}{8}\\
\dfrac{3}{4}x + \dfrac{2}{3} = 4.\dfrac{1}{8}\\
\dfrac{3}{4}x = \dfrac{1}{2} - \dfrac{2}{3}\\
\dfrac{3}{4}x = \dfrac{{ - 1}}{6}\\
x = \dfrac{{ - 1}}{6}.\dfrac{4}{3}\\
x = \dfrac{{ - 2}}{9}\\
\text{Vậy}\,x = \dfrac{{ - 2}}{9}\\
3)\dfrac{{ - 5}}{9} - \dfrac{1}{3}x = - \dfrac{2}{3}\\
\dfrac{1}{3}x = \dfrac{{ - 5}}{9} - \left( {\dfrac{{ - 2}}{3}} \right)\\
\dfrac{1}{3}x = \dfrac{{ - 5}}{9} + \dfrac{2}{3}\\
\dfrac{1}{3}x = \dfrac{1}{9}\\
x = \dfrac{1}{3}\\
\text{Vậy}\,x = \dfrac{1}{3}
\end{array}$
