原式=（x-1)/(x-3)²-1/(x-3)+2x/(x+3)(x-3)=(x²+2x-3)/(x-3)²(x+3)-(x²-9)/(x-3)²(x+3)+(2x²-6x)/(x-3)²(x+3)=(2x²-4x+6)/(x-3)²（x+3)