lim x->3 x^2-9/x^2-2x-3 x->3
Lim(x-3)(x+3)/(x+1)(x-3)=lin(x+3)/(x+1)=(3+3)/(3+1)=6/4=1,5 x²-2x-3=0 x1+x2=2 U x1*x2=-3⇒x1=-1 U x2=3