\[\frac{2x^{2} + 3x + 1}{(x + 1)(x - 3)} = 1\]
\[2x^{2} + 3x + 1 = 2\left( x + \frac{1}{2} \right)(x + 1) =\]
\[= (2x + 1)(x + 1);\]
\[D = 9 - 8 = 1\]
\[x_{1} = \frac{( - 3 + 1)}{4} = - \frac{2}{4} = - \frac{1}{2};\]
\[x_{2} = \frac{- 3 - 1}{4} = - 1.\]
\[\frac{(2x + 1)(x + 1)}{(x + 1)(x - 3)} = 1\]
\[ОДЗ:x \neq - 1;\ \ x \neq 3.\]
\[\frac{2x + 1}{x - 3} = 1\ \ | \cdot (x - 3)\]
\[2x + 1 = x - 3\]
\[x = - 4.\]
\[Ответ:x = - 4.\]