原式化为314/745*(1+x)^3=1,解之,得： x1=1/314*73454020^(1/3)-1x2= -1/628*73454020^(1/3)+1/628*i*3^(1/2)*73454020^(1/3)-1x3= -1/628*73454020^(1/3)-1/628*i*3^(1/2)*73454020^(1/3)-1