$\begin{array}{l}
a)\,\,3x\left( {2x + 5} \right) - 4x = 10\\
\Leftrightarrow 6{x^2} + 15x - 4x - 10 = 0\\
\Leftrightarrow 6{x^2} + 11x - 10 = 0\\
\Leftrightarrow \left( {3x - 2} \right)\left( {2x + 5} \right) = 0\\
\Leftrightarrow \left[ \begin{array}{l}
3x - 2 = 0\\
2x + 5 = 0
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = \dfrac{2}{3}\\
x = \dfrac{{ - 5}}{2}
\end{array} \right.\\
b)\,\,5x\left( {x - 2} \right) - {\left( {2x - 3} \right)^2} = 7 + 2x\\
\Leftrightarrow 5{x^2} - 10x - \left( {4{x^2} - 12x + 9} \right) - 7 - 2x = 0\\
\Leftrightarrow 5{x^2} - 10x - 4{x^2} + 12x - 9 - 7 - 2x = 0\\
\Leftrightarrow {x^2} - 16 = 0\\
\Leftrightarrow {x^2} = 16\\
\Leftrightarrow \left[ \begin{array}{l}
x = 4\\
x = - 4
\end{array} \right.
\end{array}$
