Odpowiedź :
[tex]x^5-2x^4-15x^3=0\\x^3(x^2-2x-15)=0\\\\\Delta=(-2)^2-4*1*(-15)\\\Delta=4+60\\\Delta=64\\x_1=\frac{2-8}{2}=\frac{-6}2=-3\\x_2=\frac{2+8}2=\frac{10}2=5\\\\x^3(x+3)(x-5)=0\\\\x_1=0\\x_2=-3\\x_3=5[/tex]
[tex]x^{5}-2x^{4}-15x^{3} = 0\\\\x^{3}(x^{2}-2x-15) = 0\\\\x^{3}(x^{2}-5x+3x-15) = 0\\\\x^{3}[x(x-5)+3(x-5)}] = 0\\\\x^{3}(x-5)(x+3) = 0\\\\x^{3} = 0 \ \vee \ x-5 = 0 \ \vee \ x+3 = 0\\\\x = 0 \ \vee \ x = 5 \ \vee \ x = -3\\\\x\in\{-3,0,5\}[/tex]