`( 1 - 2x )( 3x + 7 ) = 1 - 4x`
`\Leftrightarrow -6x^2 - 11x + 7 = 1 - 4x`
`\Leftrightarrow 6x^2 + 7x - 6 = 0`
`\Leftrightarrow ( 6x + \frac{7}{2} )^2 - \frac{193}{4} =0`
`\Leftrightarrow ( 6x + \frac{7}{2} - \sqrt{\frac{193}{4}} )( 6x + \frac{7}{2} + \sqrt{\frac{193}{4}} ) = 0`
`\Leftrightarrow x = \frac{-7\pm\sqrt{193}}{12}`
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