Odpowiedź:
[tex](x^2+2x)^2+9=6x^2+12x\\\\x^4+4x^3+4x^2+9-6x^2-12x=0\\\\x^4+4x^3-2x^2-12x+9=0\\\\x^4-x^3+5x^3-5x^2+3x^2-3x-9x+9=0\\\\x^3(x-1)+5x^2(x-1)+3x(x-1)-9(x-1)=0\\\\(x-1)(x^3+5x^2+3x-9)=0\\\\(x-1)(x^3-x^2+6x^2-6x+9x-9)=0\\\\(x-1)(x^2(x-1)+6x(x-1)+9(x-1))=0\\\\(x-1)(x-1)(x^2+6x+9)=0\\\\(x-1)^2(x+3)^2=0\\\\(x-1)^2=0\ \ \ \ \vee\ \ \ \ (x+3)^2=0\\\\x-1=0\ \ \ \ \ \ \ \ \vee\ \ \ \ \ \ x+3=0\\\\x=1\ \ \ \ \ \ \ \ \ \ \ \ \vee\ \ \ \ \ \ \ \ x=-3[/tex]
