a)
5x^2 - x^4 - 4x^3 = 0
-x^4-4x^3+5x^2=0
-x^2(x^2+4x-5)=0
-x^2(x^2+5x-x-5)=0
-x^2[x(x+5)-(x+5)=0
-x^2(x+5)(x-1)=0
-x^2=0\vee x+5=0\vee x-1=
x=0\vee x=-5 \vee x=1
b)
( x^8 - 11x^6)(x^4 - 7x^3) = 0
x^6(x^2-11)*x^3(x-7)=0
x^9(x^2-11)(x-7)=0
x^9 [x^2-(\sqrt{11})^2] (x-7)=0
x^9(x-\sqrt{11})(x+\sqrt{11})(x-7)=0
x^9=0\vee x-\sqrt{11}=0\vee x+\sqrt{11}=0\vee x-7=0
x=0 pierwiastek 9-krotny
lub
x=\sqrt{11} , x=-\sqrt{11} , x=7
c)
9x^{11} = 5x^{10}
9x^{11}-5x^{10}=0
x^{10}(9x-5)=0
x^{10}=0 pierwiastek 10-krotny
lub
9x-5=0
9x=5/:9
x=\frac{5}{9}
\vee znaczy “lub”