Đáp án:

 $1)
a)\dfrac{7}{2}\\
b)
5\\
2)
a) x=\dfrac{3}{4}\\
b) x=\dfrac{-25}{24}\\
c)
 {\left[\begin{aligned}x=2\\x=0\end{aligned}\right.}\\$

Giải thích các bước giải:

 $1)
a)7\dfrac{2}{3}:\dfrac{2}{3}-5\dfrac{1}{3}:\dfrac{2}{3}\\
=\left ( 7\dfrac{2}{3}-5\dfrac{1}{3} \right ):\dfrac{2}{3}\\
=\left [ (7-5)+\left ( \dfrac{2}{3}-\dfrac{1}{3} \right ) \right ]:\dfrac{2}{3}\\
=\left ( 2+\dfrac{1}{3} \right ).\dfrac{3}{2}\\
=\left ( \dfrac{6}{3}+\dfrac{1}{3} \right ).\dfrac{3}{2}\\
=\dfrac{7}{3}.\dfrac{3}{2}=\dfrac{7}{2}\\
b)
\left ( \dfrac{7}{10}-\dfrac{-3}{4}-\dfrac{1}{5} \right ):\left (-\dfrac{1}{2} \right )^2\\
=\left ( \dfrac{14}{20}-\dfrac{(-3).5}{20}-\dfrac{4}{20} \right ):\dfrac{1}{4} \\
=\dfrac{14+15-4}{20}.4\\
=\dfrac{25}{5}=5\\
2)
a)x-\dfrac{3}{8}=\dfrac{4}{9}:\dfrac{32}{27}\\
\Leftrightarrow x-\dfrac{3}{8}=\dfrac{4}{9}.\dfrac{27}{32}\\
\Leftrightarrow x-\dfrac{3}{8}=\dfrac{3}{8}\\
\Leftrightarrow x=\dfrac{3}{8}+\dfrac{3}{8}=\dfrac{6}{8}=\dfrac{3}{4}\\
b)\left ( 1\dfrac{2}{3}-2x \right ).\dfrac{75}{100}-2=\dfrac{13}{16}\\
\Leftrightarrow \left ( 1\dfrac{2}{3}-2x \right ).\dfrac{75}{100}=\dfrac{13}{16}+2\\
\Leftrightarrow \left ( \dfrac{5}{3}-2x \right ).\dfrac{3}{4}=\dfrac{13}{16}+\dfrac{2.16}{16}=\dfrac{45}{16}\\
\Leftrightarrow \dfrac{5}{3}-2x =\dfrac{45}{16}.\dfrac{4}{3}\\
\Leftrightarrow \dfrac{5}{3}-2x =\dfrac{15}{4}\\
\Leftrightarrow 2x=\dfrac{5}{3}-\dfrac{15}{4}\\
\Leftrightarrow 2x=\dfrac{20}{12}-\dfrac{15.3}{12}=\dfrac{-25}{12}\\
\Leftrightarrow x=\dfrac{-25}{24}\\
c)
\dfrac{2}{3}\left | x-1 \right |+\dfrac{-8}{15}.\dfrac{5}{4}=0\\
\Leftrightarrow \dfrac{2}{3}\left | x-1 \right |+\dfrac{-2}{3}=0\\
\Leftrightarrow \dfrac{2}{3}\left | x-1 \right |=\dfrac{2}{3}\\
\Leftrightarrow \left | x-1 \right |=\dfrac{2}{3}.\dfrac{3}{2}=1\\
\Leftrightarrow {\left[\begin{aligned}x-1=1\\x-1=-1\end{aligned}\right.}\\
\Leftrightarrow {\left[\begin{aligned}x=1+1\\x=-1+1\end{aligned}\right.}\\
\Leftrightarrow {\left[\begin{aligned}x=2\\x=0\end{aligned}\right.}\\$