3/x-4-24/x^2-16a+2-4/2-a2x/x-1=(1/x^2-1)+21-x/x-2=(1/2-x)-2时

3/(x-4)-24/(x^2-16) =3/(x-4)-24/[(x+4)(x-4)] =[3(x+4)-24]/[(x+4)(x-4)] =(3x-12)/[(x+4)(x-4)] =3(x-4)/[(x+4)(x-4)] =3/(x+4) a+2-4/(2-a) =[(a+2)(a-2)+4]/(a-2) =(a²-4+4)/(a-2) =a²/(a-2) 2x/(x-1)=1/(x²-1)+2 2x/(x-1)=1/[(x+1)(x-1)]+2 2x(x+1)=1+2(x²-1) 2x²+2x=2x²+1-2 2x=-1 x=-0.5 1-x/(x-2)=1/(2-x)-2 （ 第四个是这样吗？） 1-x/(x-2)+1/(x-2)+2=0 3+(1-x)/(x-2)=0 3(x-2)+(1-x)=0 3x-6+1-x=0 2x-5=0 x=2.5