Đáp án:

\(\begin{array}{l}
7,\,\,\,\,x = \dfrac{{29}}{{12}}\\
8,\,\,\,\,x = 20\\
9,\,\,\,\,x = 12\\
10,\,\,\,\,x = 10\\
11,\,\,\,\,x = 144\\
12,\,\,\,\,x = 4\\
13,\,\,\,\,x = 8\\
14,\,\,\,\,\left[ \begin{array}{l}
x = 4\\
x =  - 4
\end{array} \right.\\
15,\,\,\,\,x = 45\\
16,\,\,\,\,x = \dfrac{{89}}{2}
\end{array}\)

Giải thích các bước giải:

 Ta có:

\(\begin{array}{l}
7,\\
4 - \left( {x - \dfrac{3}{4}} \right) = 2\dfrac{1}{3}\\
 \Leftrightarrow 4 - \left( {x - \dfrac{3}{4}} \right) = \dfrac{7}{3}\\
 \Leftrightarrow x - \dfrac{3}{4} = 4 - \dfrac{7}{3}\\
 \Leftrightarrow x - \dfrac{3}{4} = \dfrac{5}{3}\\
 \Leftrightarrow x = \dfrac{5}{3} + \dfrac{3}{4}\\
 \Leftrightarrow x = \dfrac{{29}}{{12}}\\
8,\\
107 - 3 \times \left( {14 + x} \right) = 5\\
 \Leftrightarrow 3 \times \left( {14 + x} \right) = 107 - 5\\
 \Leftrightarrow 3 \times \left( {14 + x} \right) = 102\\
 \Leftrightarrow 14 + x = 102:3\\
 \Leftrightarrow 14 + x = 34\\
 \Leftrightarrow x = 34 - 14\\
 \Leftrightarrow x = 20\\
9,\\
138 - 5 \times \left( {x + 14} \right) = 8\\
 \Leftrightarrow 5 \times \left( {x + 14} \right) = 138 - 8\\
 \Leftrightarrow 5 \times \left( {x + 14} \right) = 130\\
 \Leftrightarrow x + 14 = 130:5\\
 \Leftrightarrow x + 14 = 26\\
 \Leftrightarrow x = 26 - 14\\
 \Leftrightarrow x = 12\\
10,\\
201 - \left( {36 - 4 \times x} \right) = 205\\
 \Leftrightarrow 36 - 4 \times x = 201 - 205\\
 \Leftrightarrow 36 - 4 \times x =  - 4\\
 \Leftrightarrow 4 \times x = 36 - \left( { - 4} \right)\\
 \Leftrightarrow 4 \times x = 40\\
 \Leftrightarrow x = 40:4\\
 \Leftrightarrow x = 10\\
11,\\
300 - 2 \times \left( {x + 4} \right) = 4\\
 \Leftrightarrow 2 \times \left( {x + 4} \right) = 300 - 4\\
 \Leftrightarrow 2 \times \left( {x + 4} \right) = 296\\
 \Leftrightarrow x + 4 = 296:2\\
 \Leftrightarrow x + 4 = 148\\
 \Leftrightarrow x = 148 - 4\\
 \Leftrightarrow x = 144\\
12,\\
184 - 4 \times \left( {2 \times x + 1} \right) = 148\\
 \Leftrightarrow 4 \times \left( {2 \times x + 1} \right) = 184 - 148\\
 \Leftrightarrow 4 \times \left( {2 \times x + 1} \right) = 36\\
 \Leftrightarrow 2 \times x + 1 = 36:4\\
 \Leftrightarrow 2 \times x + 1 = 9\\
 \Leftrightarrow 2 \times x = 9 - 1\\
 \Leftrightarrow 2 \times x = 8\\
 \Leftrightarrow x = 8:2\\
 \Leftrightarrow x = 4\\
13,\\
3 \times x + 4 \times x - 15 = 41\\
 \Leftrightarrow x \times \left( {3 + 4} \right) = 41 + 15\\
 \Leftrightarrow x \times 7 = 56\\
 \Leftrightarrow x = 56:7\\
 \Leftrightarrow x = 8\\
14,\\
\left[ {x \times x + 55 - 31} \right] \times 14 = 560\\
 \Leftrightarrow x \times x + \left( {55 - 31} \right) = 560:14\\
 \Leftrightarrow x \times x + 24 = 40\\
 \Leftrightarrow x \times x = 40 - 24\\
 \Leftrightarrow x \times x = 16\\
16 = 4 \times 4 = \left( { - 4} \right) \times \left( { - 4} \right)\\
 \Rightarrow \left[ \begin{array}{l}
x = 4\\
x =  - 4
\end{array} \right.\\
15,\\
\left[ {43 - \left( {56 - x} \right)} \right] \times 12 = 384\\
 \Leftrightarrow 43 - \left( {56 - x} \right) = 384:12\\
 \Leftrightarrow 43 - \left( {56 - x} \right) = 32\\
 \Leftrightarrow 56 - x = 43 - 32\\
 \Leftrightarrow 56 - x = 11\\
 \Leftrightarrow x = 56 - 11\\
 \Leftrightarrow x = 45\\
16,\\
\left( {x + 1} \right) + \left( {x + 2} \right) - 47 = 45\\
 \Leftrightarrow x + 1 + x + 2 - 47 = 45\\
 \Leftrightarrow \left( {x + x} \right) + \left( {1 + 2 - 47} \right) = 45\\
 \Leftrightarrow 2 \times x - 44 = 45\\
 \Leftrightarrow 2 \times x = 45 + 44\\
 \Leftrightarrow 2 \times x = 89\\
 \Leftrightarrow x = 89:2\\
 \Leftrightarrow x = \dfrac{{89}}{2}
\end{array}\)