中间错了原式=(x+2)/(x-3)(x+2)+2x/x(x-3)-(x+1)/(x-3)²=1/(x-3)+2/(x-3)-(x+1)/(x-3)²=3/(x-3)-(x+1)/(x-3)²=[3(x-3)-(x+1)]/(x-3)²=(2x-10)/(x-3)²