(8x-3)(3x+2)-(4x+7)(x+4)=(2x+1)(5x-1)

$\begin{array}{l} \left( {8x - 3} \right)\left( {3x + 2} \right) - \left( {4x + 7} \right)\left( {x + 4} \right) = \left( {2x + 1} \right)\left( {5x - 1} \right)\\  \Leftrightarrow 24{x^2} + 16x - 9x - 6 - \left( {4{x^2} + 16x + 7x + 28} \right) = \left( {10{x^2} - 2x + 5x - 1} \right)\\  \Leftrightarrow 24{x^2} + 7x - 6 - 4{x^2} - 23x - 28 = 10{x^2} + 3x - 1\\  \Leftrightarrow 20{x^2} - 16x - 34 - 10{x^2} - 3x + 1 = 0\\  \Leftrightarrow 10{x^2} - 19x - 33 = 0\\  \Leftrightarrow 10{x^2} - 30x + 11x - 33 = 0\\  \Leftrightarrow 10\left( {x - 3} \right) + 11\left( {x - 3} \right) = 0\\  \Leftrightarrow \left( {x - 3} \right)\left( {10x + 11} \right) = 0\\  \Leftrightarrow \left[ \begin{array}{l} x = 3\\ x =  - \dfrac{{11}}{{10}} \end{array} \right.\\  \Rightarrow S = \left\{ {3; - \dfrac{{11}}{{10}}} \right\} \end{array}$