[tex]x^{2}(x+1)+x(x+1)-2(x+1) = 0\\\\(x+1)(x^{2}+x-2) = 0\\\\x+1 = 0 \ \ \rightarrow \ \ x = -1\\\\Lub\\\\x^{2}+x-2 = 0\\\\a = 1, \ b = 1, \ c = -2\\\\\Delta = b^{2}-4ac = 1^{2}-4\cdot1\cdot(-2) = 1+8 = 9\\\\\sqrt{\Delta} = \sqrt{9} = 3\\\\x_1 = \frac{-b-\sqrt{\Delta}}{2a} = \frac{-1-3}{2\cdot1} = \frac{-4}{2} = -2\\\\x_2 = \frac{-b+\sqrt{\Delta}}{2a} = \frac{-1+3}{2} = \frac{2}{2} = 1\\\\\boxed{x = -2 \ \vee \ x = -1 \ \vee \ x = 1}[/tex]
