[tex]x^5+2x^4-3x^3=0\\\\x^3(x^2+2x-3)=0\\\\x^3(x^2-x+3x-3)=0\\\\x^3[x(x-1)+2(x-1)]=0\\\\x^3(x+2)(x-1)=0\\\\x^3=0\quad\vee\quad x+2=0\quad\vee\quad x-1=0\\\\x=0\quad\vee\quad x=-2\quad\vee\quad x=3[/tex]
[tex]x^3-5x^2+7x-35=0\\\\x^2(x-5)+7(x-5)=0\\\\(x-5)(x^2+7)=0\\\\x-5=0\ \quad\vee\quad x^2+7=0\\\\x=5\ \ \ \qquad\vee\quad x^2=-7\ \ \{sprzeczno\'s\'c\}\\\\x=5[/tex]
[tex](3x-1)(5x+15)(4-2x)=0\\\\3x-1=0\quad\vee\quad5x+15=0\quad\vee\quad4-2x=0\\\\3x=1\ \ \qquad\vee\quad5x=-15\qquad\vee\quad-2x=-4\\\\{}\ x=\frac13\ \ \qquad\vee\quad{}\ x=-3\qquad\vee\quad\ \ x=2[/tex]
