(x-3)^2/(x+2)(x-2)=0/(5*1)=0
(x^2-6x+9)/(x^2-4)=(x-3)²/(x²-4)=(3-3)²/(3²-4)=0
(x^2-6x+9)/(x^2-4)=(x-3)^2/(x+2)(x-2)=0
等于0 (X+3)(x—3)/(x+2)(X—2) 因为x=3所以 等于0
原式=(x-3)^2/((x-2)(x+2))代x=3得,原式=0