Ma puteți ajuta va rog, dau steluta

x-2=0,x+1=0,x=0,x=2,x=-1,x-0,S=2+(-1)+0=1
(((2/(x-2))-((2/(x+1)))·(x(x+1)(x-2))/2=((2x+2-2x+4)·x)/2=6x/2=3x
b. (x^2)+2·3x+9=(x^2)+6x+9=(x+3)^2