2.
[tex]W(x) = x^{4}+3x^{3}+4x^{2} = x^{2}(x^{2}+3x+4)[/tex]
3.
[tex]x+1 = \frac{2-2x}{x-1} \ \ /\cdot(x-1)\\\\\\Z:\\x-1 \neq 0\\x \neq 1\\D = R \setminus\{1\}\\\\\\(x+1)(x-1) = 2-2x\\\\x^{2}-1 = 2-2x\\\\x^{2}+2x-1-2 = 0\\\\x^{2}+2x-3 = 0\\\\a = 1, \ b = 2, \ c = -3\\\\\Delta = b^{2}-4ac = 2^{2}-4\cdot1\cdot(-3) = 4+12 = 16\\\\\sqrt{\Delta} = \sqrt{16} = 4\\\\x_1 = \frac{-b-\sqrt{\Delta}}{2a} = \frac{-2-4}{2\cdot1}=\frac{-6}{2} = -3\\\\x_2 = \frac{-b+\sqrt{\Delta}}{2a} = \frac{-2+4}{2} = \frac{2}{2} = 1 \ \notin D\\\\\boxed{x = -3}[/tex]
