Odpowiedź:
[tex]x^{4}+11x^{3}+28x^{2}=0\\x^{2}(x^{2}+11x+28)=0\\x^{2}=0\\x=0 \\lub\\delta = 121-112=9\\x_{1}= (-11+3)/2=-4\\x_2 =(-11-3)/2=-7[/tex]
