= [(x+3)(x-3)-7]/(x-3) 2(x-3)/(x²-8x+4²)= 2 (x²-4²) / (x-4)²=2(x+4)(x-4)/(x-4)²=2(x+4)/(x-4)当x=2^-3=1/8时原式=2(1/4+4)/(1/4-4)=-66/31