Đáp án:

$\begin{array}{l}
B2)1)\left( {3x - 8} \right)\left( {4 - 5x} \right) = 0\\
 \Leftrightarrow \left[ \begin{array}{l}
3x - 8 = 0\\
4 - 5x = 0
\end{array} \right.\\
 \Leftrightarrow \left[ \begin{array}{l}
x = \dfrac{8}{3}\\
x = \dfrac{4}{5}
\end{array} \right.\\
Vậy\,x = \dfrac{8}{3};x = \dfrac{4}{5}\\
2)\left( {5 - 4x} \right)\left( {2 - 3x} \right) = 0\\
 \Leftrightarrow \left[ \begin{array}{l}
x = \dfrac{5}{4}\\
x = \dfrac{2}{3}
\end{array} \right.\\
Vậy\,x = \dfrac{5}{4};x = \dfrac{2}{3}\\
3)\left( {15 - 3x} \right)\left( {9 - 4x} \right) = 0\\
 \Leftrightarrow \left[ \begin{array}{l}
x = 5\\
x = \dfrac{9}{4}
\end{array} \right.\\
Vậy\,x = 5;x = \dfrac{9}{4}\\
4)\left( {3x - 4} \right)\left( {5 - 6x} \right) = 0\\
 \Leftrightarrow \left[ \begin{array}{l}
x = \dfrac{4}{3}\\
x = \dfrac{5}{6}
\end{array} \right.\\
Vậy\,x = \dfrac{4}{3};x = \dfrac{5}{6}\\
5)\left( {5x - 7} \right)\left( {x - 5} \right) = 0\\
 \Leftrightarrow \left[ \begin{array}{l}
x = \dfrac{7}{5}\\
x = 5
\end{array} \right.\\
Vậy\,x = \dfrac{7}{5};x = 5\\
6)\left( {3x - 7} \right)\left( {x + 5} \right)\left( {2x - 1} \right) = 0\\
 \Leftrightarrow \left[ \begin{array}{l}
x = \dfrac{7}{3}\\
x =  - 5\\
x = \dfrac{1}{2}
\end{array} \right.\\
Vậy\,x = \dfrac{7}{3};x =  - 5;x = \dfrac{1}{2}\\
7)\left( {13 - 7x} \right)\left( {6 - 8x} \right)\left( {9 + 5x} \right) = 0\\
 \Leftrightarrow \left[ \begin{array}{l}
x = \dfrac{{13}}{7}\\
x = \dfrac{6}{8} = \dfrac{3}{4}\\
x = \dfrac{{ - 9}}{5}
\end{array} \right.\\
Vậy\,x = \dfrac{{ - 9}}{5};x = \dfrac{3}{4};x = \dfrac{{13}}{7}\\
9)\left( {170 - 2x} \right)\left( {9 - 5x} \right)\left( {13 - 6x} \right) = 0\\
 \Leftrightarrow \left[ \begin{array}{l}
x = \dfrac{{170}}{2} = 85\\
x = \dfrac{9}{5}\\
x = \dfrac{{13}}{6}
\end{array} \right.\\
Vậy\,x = \dfrac{9}{5};x = \dfrac{{13}}{6};x = 85\\
10)\left( {5x - 9} \right)\left( {13 - 5x} \right)\left( { - 7 + 5x} \right) = 0\\
 \Leftrightarrow \left[ \begin{array}{l}
x = \dfrac{9}{5}\\
x = \dfrac{{13}}{5}\\
x = \dfrac{7}{5}
\end{array} \right.\\
Vậy\,x = \dfrac{7}{5};x = \dfrac{9}{5};x = \dfrac{{13}}{5}\\
1)3\left( {2x - 5} \right) + 6\left( {x - 9} \right) = 7\\
 \Leftrightarrow 6x - 15 + 6x - 36 = 7\\
 \Leftrightarrow 12x = 58\\
 \Leftrightarrow x = \dfrac{{29}}{6}\\
Vậy\,x = \dfrac{{29}}{6}\\
2)6\left( {5 - 7x} \right) - 5\left( {6 + 3x} \right) = 12\\
 \Leftrightarrow 30 - 42x - 30 - 15x = 12\\
 \Leftrightarrow 57x =  - 12\\
 \Leftrightarrow x = \dfrac{{ - 4}}{{19}}\\
Vậy\,x = \dfrac{{ - 4}}{{19}}\\
3)2\left( {6 - 4x} \right) - 8\left( {5 - 7x} \right) = 15\\
 \Leftrightarrow 12 - 8x - 40 + 56x = 15\\
 \Leftrightarrow 48x = 43\\
 \Leftrightarrow x = \dfrac{{43}}{{48}}\\
Vậy\,x = \dfrac{{43}}{{48}}\\
4) - 4\left( {6 - 7x} \right) + 5\left( { - 6 - 5x} \right) = 20\\
 \Leftrightarrow  - 24 + 28x - 30 - 25x = 20\\
 \Leftrightarrow 3x = 14\\
 \Leftrightarrow x = \dfrac{{14}}{3}\\
Vậy\,x = \dfrac{{14}}{3}\\
6)15\left( {3x - 7} \right) + 4\left( {x - 5} \right) = 12\\
 \Leftrightarrow 45x - 105 + 4x - 20 = 12\\
 \Leftrightarrow 49x = 137\\
 \Leftrightarrow x = \dfrac{{137}}{{49}}\\
Vậy\,x = \dfrac{{137}}{{49}}\\
7)8\left( {x + 5} \right) - 9\left( {6 - 4x} \right) = 0\\
 \Leftrightarrow 8x + 40 - 54 + 36x = 0\\
 \Leftrightarrow 44x = 14\\
 \Leftrightarrow x = \dfrac{7}{{22}}\\
Vậy\,x = \dfrac{7}{{22}}\\
8)7\left( {x - 5} \right) + 4\left( {6 - 5x} \right) = 4\\
 \Leftrightarrow 7x - 35 + 24 - 20x = 4\\
 \Leftrightarrow 13x =  - 15\\
 \Leftrightarrow x = \dfrac{{ - 15}}{{13}}\\
Vậy\,x = \dfrac{{ - 15}}{{13}}
\end{array}$