1
x1=6 x2=-3
p=-(x1+x2)=-(6-3)=-3
q=x1*x2=6*(-3)=-18
x²-3x-18=0
2
(x²-6x)/3=x/*3
x²-6x=3x
x²-6x-3x=0
x(x-9)=0
x=0 x=9
3
(x²-x)/2+x/3=0/*6
3x²-3x+2x=0
3x²-x=0
x(3x-1)=0
x=0 x=1/3
4
(x²-4)-(x²-1)/3=-1/*15
3(x²-4)-5(x²-1)=-15
3x²-12-5x²+5=-15
-2x²=-15+7
-2x²=-8
x²=4
x=-2 U x=2