(X+8)/(30+8+X)=3/1

1个回答

  • [1/(x-1)(x+2)]+[1/(x+2)(x+5)]+[1/(x+5)(x+8)]+[1/(x+8)(x+11)]=(1/3x-3)-1/24(1/3)[1/(x-1)-1/(x+11)]=1/[3(x-1)]-1/241/(x-1)-1/(x+11)=1/(x-1)-1/81/(x+11)=1/8x=-3