a)
[tex]x^{4} + 6x^{3} + 5x^{2} = 0\\x^{2}(x^{2} + 6x + 5) = 0\\\\x^{2} = 0 \\x = 0\\\\x^{2} + 6x + 5 = 0\\delta=36-4*5*1 = 36-20 = 16\\\sqrt{delta} = \sqrt{16} = 4\\x_{1} = \frac{-6-4}{2} = \frac{-10}{2}= -5 \\x_{2} = \frac{-6+4}{2} = \frac{-2}{2} = -1\\\\x = 0\\x = -5\\x = -1[/tex]
b)
[tex]2x^{3} + 5x^{2} + 2x = 0\\x(2x^{2} + 5x + 2) = 0\\\\x = 0\\\\2x^{2} + 5x + 2 = 0\\delta = 25 - 4*2*2 = 25 - 16 = 9\\\sqrt{delta} = \sqrt{9} = 3\\x_{1} = \frac{-5-3}{4}= \frac{-8}{4} = -2\\x_{2} = \frac{-5+3}{4}=\frac{-2}{4} = -\frac{1}{2}\\\\x = 0\\x = -2\\x = -\frac{1}{2}[/tex]
